What about 
What about lionsoda I'll put everything in a spoiler so I don't take up too much space-
Bounsweet: The first thing I saw on his profile was that he liked fruit and bounsweet was the first pokemon to come to mind! I don't think there's any strawberry or watermelon adjacent pokemon, so I went with the first fruit-like pokemon to come to mind. I thought about putting the full evolution here, but Tsareena isn't quite as fruit like as Bounsweet. I also thought Bounsweet's personality was more fitting for Ryu too... also fun fact that I didn't know but Bounsweet is probably based off the purple mangosteen which is a tropical fruit! So that seemed fitting.
Scyther: He likes praying mantis'... so I thought he'd probably like Scyther too. Also similar to Bounsweet where I thought Scyther looked more similar to a praying mantis than Scizor or Kleavor, but either of those two would've worked as well. This one isn't super in depth just... mantis pokemon!
Palossand: Being in a tropical climate and liking to swim a lot makes me think of... well beaches and sand, so I thought Palossand would be fitting! It also says he likes lying in the sand which is why I chose Palossand over Alolan Exeggutor. I don't know if he'd enjoy building sand castles, but having a sand based pokemon to hang out with while just enjoying the sand seemed like a fun idea to me.
Heliolisk: Since Ryu's a gecko I really wanted to give him a lizard or reptile pokemon of some kind. I was VERY close to going with Charmander, but then I remembered Heliolisk and I think it fits him so much better. While Charmander is a fire type, Heliolisk basically embodies the sun and Ryu likes the sun! It's hidden ability is literally called solar power lol. On top of that it also evolves with a sun stone, and I think it would have a much more lively and energetic personality than Charmander. Also since Ryu doesn't really like when it's too hot an electric-type lizard which still has references to the sun seemed better than a fire type.
Mantine: Since he loves to swim and has a very tropical theme I wanted to give him some kind of water type and preferably one that would fit in tropical areas. There were a lot that fit, but I went with Mantine in the end because a lot of it's pokedex entries mention how it loves to swim freely in the sea. It's also pretty carefree and always smiling so I thought it would be the most fitting for Ryu. Mantyke itself is also pretty friendly, so I just think it'd be cute if Ryu made friends with a Mantyke after moving somewhere tropical and it eventually evolved into a Mantine.
Glaceon: Because he originally grew up in a colder climate and misses the snow somewhat I wanted to give him an ice type! I thought about going with Walrein since it was a dual ice and water type, but I eventually went with Glaceon instead. This is largely because of Glaceon's ability to freeze the air around it. I thought Ryu might appreciate that ability on days where it's far too hot out, but it's also possible that Glaceon could help with making mini snowstorms whenever he's feeling homesick. The storms probably wouldn't last long at all in tropical weather, but it still might be nice.
Next person: You're welcome to do IC or anyone here that catches your eye. No preference really-
I think Roserade was the first pokemon she ever got, part of why she has a rose tattoos. They're matching! Imagine a lil pup Morana with a baby budew ;u;
