The Wyld Stallyns were a pretty eclectic band; they had a couple of slackers, time displaced princesses, an alien (or two depending), robots, and even the Grim Reaper.
Using live action movie and TV characters, make yourself a gnarly band.
You can structure your band however you like, as deep as you want.
You can’t use characters from the actual Bill & Ted movies, but other than that, enjoy!