Well, this may be hard given half the cast doesn't have fingers (chickens)
Alec Tryon would definitely play guitar.
Luke Tryon, maybe bass guitar or drums, doesn't want to be at the front, that's for sure.
Aldi, violin or piano, cause she's the most educated of the group.
Carl, obviously a banjo, gotta keep up the stereotype! (I got hillbilly in my heritage, so it's ok)
Uh, not sure Friar would play anything, maybe crow (sing) -very badly. Same for Gallus.
Bucky would just stand there, unsure of how to play anything.
Actually, I can see all of the chickens pecking at keys on a piano and jumping on them trying to play chords XD
For the record, I do plan to have an upcoming character playing the mandoline (the slicing tool) fitted with strings like a mandolin. And what's funnier is that he's a Mandarin duck.
A Mandarin playing the mandoline like a mandolin. That's gonna be fun to draw...It'll be a while though...