>>695772
I don't self-insert, so this is just me trying to be objective.
Wise is more down to earth and business savvy, so it makes more sense to me for him to be the one to hold down the fort. Handling most parts of the video store, their expenses, etc. I can see him as the one who does most of the mapping out for hollows as well. Belle just doesn't seem to have the attention span for more mundane tasks like that.
Belle fits a lot better for social interactions, doing outside tasks, and for possessing Eous though. Wise is kind of autistic and plain, which fits his character. Belle is bubbly and bursting with personality, which shines through when interacting with agents or moving around as a bangboo. I personally find her more fun to play as, but I can see her appeal as the colorful secondary character as well.
>>695789
Astra Yao will feel weird no matter which you're playing as, it had some pretty abysmal pacing. Vivian arc felt perfectly fine as a Bellefag though. I think it's up to personal taste since I can't imagine Wise being the one she obsesses over. I prefer the story focusing on one of them while the other is more of a support. Both of them being present at all times would make a lot of scenes awkward and get old fast. Can't really allow players to freely switch between them and replace each other in the story either since that breaks the narrative.