Your OC families

i'm gonna talk human AU since my OCs all have big families there! (also using human AU names but i'll link to their profiles)

- helen is a mother (the father lives in america doing overseas work so he's rarely home) who has two daughters being danielle and lauren! she's a christian mother but doesn't mind that neither of her children follow the religion and she's very kind, empathetic, and understanding (which is where dani gets a lot of her personality from)
she finds it funny that her youngest daughter jokes about being the antichrist and is weirdly supportive of her heavy goth phase and how she spends all her money in hot topic - she's just supportive of everything her daughters do and has never even batted an eye to dani's pokemon obsession despite her eldest being in her late 20s!
one day - about six years ago - two young boys (one of which was terribly injured) ran into her in the town while her daughters were shopping in a small store and begged her for her help - she took them to hospital and found out that they were both illegal immigrants from north korea who's father had been abusing them horribly and caused the elder boy's injuries
her Mum Mode kicked in and she immediately starting working out how she could adopt the two (thru her lawyer powers idk how that stuff works just imagine i do) and after a long while (and once their father was .... gone i guess still don't know whether he'd go to jail or get sent back - once again, don't know these things) she managed to adopt kiyung and jaehyuk and now had two sons in her family! they proved to be difficult to handle with their differing mental disorders, but she's incredibly supportive, patient, and understanding of the two and love them dearly!
once ki and jae came out of their shells, they started adding real personality to their household and there was never a dull moment when they were around (mostly ki and rahart - jae's alter, jae himself is fairly quiet and shy but has his quirks)
all the siblings get along very well and it's one of the most loving, caring, fun, and friendly households in the town!

- travis and caleb are siblings that simply DO NOT GET ALONG - being the middle and youngest child, one would expect that travis is an asshole and caleb is a massive whiny bitch that gets his parents to give him whatever he wants
caleb is fairly polite (a little rude at times) and basically mute outside his home, but as soon as he gets home he finds his voice and his attitude and knows exactly how to use it. he deliberately pisses travis off and while trav is very formal and polite, he doesn't hesitate to knock some sense into the kid on the regular
they have an older sister called leah who managed to keep the peace within their family, but she moved out in order to go to university to do long-term study so they don't see her that often
their parents, however, don't really do anything to quell the constant fighting and probably wouldn't blink if they started throwing expensive vases at each other from opposite ends of the room
they're a part of a very rich family and live in a two-storey expensive looking house that has marble floor and lots of gold and silver in the interior - it's fairly empty and is always spotless of mess

- much like in his regular verse, adrian and his parents don't have contact after he ran away from home and ended up living w/ his best friend mini. his parents (avery & audrey) couldn't care less, but his mum does still somewhat keep in contact with him just to make sure he's doing alright. mini's adoptive parents were more than happy to accommodate adrian and he's happy that he has a loving family to take care of him even if it's not his own

- actino and epsilo are siblings that are born seventeen years apart so it's to be expected that epsilo really hated actino for most of the younger's life. it wasn't until ac was kicked out of his parent's home for being gay and turned up on ep's door did he start to become almost a third parent to his brother and took him under his wing
he takes care of ac and gave him a room in his house, and did everything like help him with his assessments and help him get his driving license ect - ac's really indebted to epsilo and has always looked up to him his whole life and the two's relationship went from distant to incredibly close since they started living together
ep's now super protective of actino and neither particularly keep in contact w/ their parents due to actino's homosexuality and epsilo dating a transwoman (mejara) - which his parents don't know about, all they know is he has a girlfriend but nothing more, but he's cut contact w/ them regardless esp after the actino incident

i could probably keep going but considering EVERY SINGLE ONE OF MY OCS are apart of this massive AU and all of which have families i feel it'd make the list too long so here's four :'3

i think i went kinda off tangent from the questions but hey! i do love figuring out my OCs families and i can imagine exactly what their houses would look like, how they'd all interact w/ each other, how rich each family is, which OCs parents give them allowances and which don't, what 'rules' parents have for their kids to follow, which OCs would be given curfews, what the parents' jobs are and how often they're home/work hours ect ect :'D

that might depend, most of my main characters together form a so called /glittergoth family/, but as far as the biological families go it's like this

Andrej and Nina are brother and sister who are very close, Andrej works together with his father Richard so they spend more time together, theis mother Bunny likes to invove with herself not only in her kids lives but also their friends if necessary. they both are pretty close with their parents, tho Nina often disagrees with some of her mother's ~overly open about sex~ views

Andreja lives with ther brother Peter and works with ther father John, their mother is yet to make an appearance, but there's no reason to not believe they are a close family.

Cereal Killer doesn't know who his real parents are, but tries to stay close with the parents who raised him, they are the only parents he ever knew and also loves them as such. they live on the opposite sides of the world now tho so they stay in touch manly through internet

Jure had a falling out with his father a while ago, he's probably still staying in touch with his mom, but there's not much about that in the actual comics

Scarlett had her whole family worked out in the old comics as Mr. Mole, but after renovating the comics all that's left of that family is her cousin, better known as Therapist. they are not super close, but therapist is very involved with Scarlett's freinds' lives as a lot of them need therapy. her parents very likely live in another part of the world, but hasn't really appeard in the comics yet. Some old sketch and a picture of her parents in one comics show that she has two dads and one of them is a fairy.

Simon also works with his father for sure, but his parents haven't made the actual appearance yet

Tadej works with his father, but his mother died when he was a kid. His father is probably the only person Tadej actually respects

Tim doesn't know his father and has a bit troubled relationship with his mom but they stilll spend a lot of time working together on some projects. He also has a father, a half-brother and half-sister he is yet to meet.

I have yet to acquire any good information about Jade's and Tina's families

I think an OCs family is really important to how they are as a person! Now I often feel like I'm taking the easy way out if I'm fleshing a family tree out to an important OC's grandparents. Of course, this is a lot of work and doesn't happen overnight. I feel like the more "bonds" a character has to a world the more developed and interesting they are generally.

Also there are so many different family dynamics to play with! Nuclear, extended, single parents, foster parents, found families, ect.

I think a great tool for this is the sims actually! I know not everyone's into games, but it's helpful in making family trees and you can play with genetics to make grandparents, aunts, uncles, ect. 

For Al'theo's background I wound up writing a timeline briefly on how his grandparents met and then going more in depth about his own parents and eventually his early life. I felt like this REALLY helped me roleplay him! I understood how he was raised where he got his personality from. Highly recommend this, even if the OC's parents' aren't important to them or even AWFUL to them. 

My characters' families are always firmly in the background, even when they are pretty well fleshed-out. I usually have at least some vague idea of what they're like, though - family is very important to a character's history and personality and all, but it's not a topic I really feel like exploring in depth right now; I'll leave that to writers who can make it feel natural and not stilted and actually fun and entertaining for now. Eventually, maybe, when the mood strikes. 

Here's a short breakdown of my protagonists' families:

DOAMS

Augustus von Langenstein is a vampire, his parents were his entire family, and they've been dead for almost 250 years. In life, they were well-meaning but horrible at parenting: cold, ambitious and often inadvertently cruel. They wanted to give their only son the best possible shot at maintaining the family's legacy, really did the best they could - and it almost broke him. You can read up on his backstory in his profile - it's a long, long story.

Jaime Peterson has probably the biggest and most vibrant family out of the bunch: mother, father, four brothers, humongous old family dog. Jaime lives a few towns over from most of her family and is in regular contact with almost all of them - she's 22 years old and moved out not too long ago, and even though she's not on her own, her parents worry nonetheless. Her mom is an astrophysics professor at a nearby university (the same one Jaime went to, actually), her dad teaches German and Latin at a local secondary school (link goes to a wikipedia article about the specific kind of secondary school, so that nobody involved in children's education murders me; it's essentially just high school, though). Jaime wanted to follow in his footsteps (except with English instead of German), which failed when Jaime figured out that teaching isn't nearly as fun when she's the one doing it. Her oldest brother (28 years old) has some boring-but-reasonably-well-paid desk job which he genuinely enjoys (to Jaime's constant confusion) and is currently engaged to his girlfriend of nine years - they've been meaning to marry for ages, but keep putting it off because they both suck at organizing things. The second oldest brother (26) is the one Jaime has always been closest to - he's a philosophy major (and has gone through at least half a dozen minors) and a bit of an airhead. Fond of philosophizing (... obviously), being a constant but oddly charming know-it-all, annoying his younger sister, and complaining about his Flatmates From Hell. Jaime is the only one in her family with magical abilities, she's got a job that came with some really sweet living space and she's generally way too lucky. That, her brother doesn't mind - as long as his sister is happy, he's happy for her. Her cute, sweet, polite, soft-spoken, extremely orderly room-mate, though? Yeah, her brother sure wouldn't mind trading him for the Abyssal Flat-Share. Then Jaime's got two younger brothers: Twins, 15 years old and almost as much of an overly-energetic bouncy nightmare as young Jaime used to be. The dog is ten years old, pitch-black, 90% floof, and about twice as large as a dog could reasonably be expected to be.
Bonus: Her parents are gigantic science fiction geeks; Star Trek is their favorite thing. They met at a Trek convention, both cosplaying as Spock. One of the kids bought them matching Star Trek uniform pajamas many years ago; teenaged Jaime thought it was the most embarrassing thing in the universe; present-time Jaime thinks it's hilarious.

Equinox

Absalom Hayes's family is... mostly dead, really. Father was an old-timey wooden-ships-and-iron-men naval officer... who died on land, interestingly. His mom was a tailor, who died of regular old sickness - flu, followed by pneumonia. He also has a younger brother, who ran away and vanished after he grew tired of his overly doting yet constantly absent older brother and his sad and empty family home. Absalom still misses all of them terribly.

Severin Lapointe's family, in contrast, is still alive and well; his parents are enjoying retirement in the same place they worked at: a very picturesque little village up north, which had always been a popular vacation spot. He also has at least one uncle, who's a travelling merchant, and a sister named Andromeda. Might even be his twin, haven't quite decided on that yet - in any case, they're pretty close in age. Andromeda is a battlemage like Severin, but she stays mostly behind the lines, researching offensive spells and generally blowing stuff up. She loves her job. They are in reasonably regular contact as far as their jobs allow, but their relationship has always been dominated by friendly sibling rivalry and incessant snarking.