Actually, it's spelled Bobobo-Bo Bo-Bobo, but that's beside the point.
Yeah, it should be decently easy. Thanks to the aforementioned GBA sprites, I already have all the colors I need. The trick is properly conveying his emotions from each perspective.
I'm thinking a confident grin when he's just standing, a smile with the teeth exposed (a la the above Knux image) while running, eyes closed when jumping, starry eyes and a huge smile when "flying" abilities, and a wide eyed scream whenever attacked or killed.
As for sound effects, here's what I have so far:
Taunts:
"Churros! Get your churros!"
"Fuzzylicious!"
"How you like me now?!"
*maniacal laughter*
"Magic-Wand-Oh!"
Flight:
"Tweettweettweettweettweettweettweettweet..."
Hurt/killed:
"CHURROOOOOOOOOOOS!"
"NOOOOOOOOOOOOO!"
"Grrrrr....."
If someone could even figure out a way to either get him to throw churros instead of rings or be able to swing the Don Patch sword (in all its "IT'S A GREEN ONION!!!!" glory), that would be awesome beyond belief.