Unequivocally Cocka-Cocka wins hands down. He is the most powerful fighter (with Cockatrix) and the most balanced spell caster and an absolute powerhouse maxed out. His dance is very cute and even without dialogue is still the most loveable.
Luby is adorable with a lovely compassionate caring soul and had some really good skills as a fighter and spellcaster.
Spark was cute but not that strong.