Well, I tried. I don't have a char fit for Scooby, unfortunately, unless maybe I use a rubber chicken or something XD This was fun, tho.

Friar = Daphne, cause why not?
Bucky = Shaggy, cause he loves to eat
Gallus = Fred, cause he's the leader of the troupe
(To-appear char)Nixworth = Velma, cause he's a nerd (although Dr Fowler would fit here too, also nerd)