now that I ACTUALLY know the bare minimum of DnD, I can answer this! jacksy would be a spellcaster of some kind, thalasso maybe a wizard, lyn would be a funny bard, nomai would be a fighter or barbarian!

for dr moby i think theyre a cleric bc they resonate alot w em lorewise but also bc moby is more of a supporter and has the best utility if they were in combat

bratsche would probably be a bard but would lack half of the charisma of one because of how focused she is on her hobby
(>knows almost nothing about dnd)

linni would be an artificer I think!

Blue would be a Ranger specializing in forests and I don't know what his favored enemy would because he's not much of a fighter. he would be THE ONE melee Ranger!!

Sigma would be a Bard that doesn't know how to flirt