These are all some very nice ideas, for sure! O:
Jacob would probably make a great paladin, with a huge shield and some kind of hooded cape (#aesthetic). He will protect the innocent!
Bowman would definitely fit as a druid. There’s also a prestige class in at least one version of D&D called a Scout that is pretty much exactly what Bowman is. Little green leafy scout.
I think Oscar would be more likely to be a rogue/thief than a bard, because one of the key differences between them is bards kinda get their skills from being loud … though now I can’t help but imagine wee little Oscar making quiet little tunes to help his buddies. He’d be the cutest little support ever.
Honestly, between the three of them, that’s not a terrible party makeup.