I feel like Bell would get along with Leap pretty well! Even if they don't end up being friends, I think they wouldn't have too many issues living as roommates.
Bell would definitely try to put in the effort to be friends, he thinks as birds they gotta stick together! However, their first road bump might be Bell's tendency to tease and play pranks. Since Leap doesn't let things go, this might cause some friction between them. Bell is a pretty smart guy but I don't think he'd pick up the reason for the friction at first, he's just being himself and thinks he's being friendly. Once he figures out what the issue is, or if Leap straight up tells him, he'll definitely tone it down. He can't get rid of his mischievous nature entirely, but he'll try his best not to annoy Leap too much, and will try to make up for it by cleaning their communal living spaces obsessively.
Something that they share is their love for creating music! Bell would certainly love to talk and discuss music, not to mention listen to whatever Leap has created. Bell doesn't create music as much as he did before, since he's so invested in his ASMR YouTube channel, but he would want to share the music he does occasionally create when inspiration hits. If they get pretty close, Bell would also let Leap borrow his very expensive and nice mics for any music needs he might have. He might want to watch him use them, just in case, but he'll still let the other bird use them.
I'm not sure what Bell would do about Leap locking himself away for projects. I think in the beginning Bell wouldn't want to intrude, since Bell himself wouldn't want to be interrupted when he's making a video. As time goes on though, he'll notice Leap spends an unhealthy amount of time by himself when he's working on something, so he might try to start coaxing him out to take breaks. He probably wouldn't have the muscle to physically drag him away though.
⇩ Oh, they would certainly make interesting roommates! Hopefully Bell doesn't annoy Lietu too much and vice versa. Their contrasting personalities would make that first initial week a bit of a struggle, I think, as they try to figure each other out. Communication may be a bump in the road, since the only way kenkus can really communicate is through sign language or mimicry, which combined with Leitu's shyness may create a barrier of some kind. It might force Leitu to speak more though, who knows? However, once they have something worked out, I can see them getting along pretty smoothly.
Bell would take delight in a person that's alright with pranks! Not a lot of people are alright with them, and the ones that do like them end up trying to drag him into prank wars, which he does not enjoy. He doesn't like competing and finds that prank wars escalate over the line. So to have someone that just let's him do them and then have yokai scheme with him? Oh, he'd enjoy it immensely.
Being given space for his projects is something Bell will always be grateful for and he'll do the same in return. Like, he'd let Lietu practice his instruments in peace, and only bombard him about said instruments after he's done. Bell would be super interested in them and would probably draw inspiration from them in a new piece. Given Lietu is fine with it, he would love to actually collab with him rather than using synthesized versions of the instruments, it would be much more authentic and probably sound better.