Easiest
KH: Clayton, even with the stealth sneak
COM: Jafar and Ursula were both easy
KH2: Shan-Yu
BBS: Lucifer by far
3D: Purple Fat lady- easiest boss in KH history
Hardest
KH: Dragon Maleficent
COM: Dragon Maleficent
KH2: Oogie and Pete were both longish fights
BBS: Captain Hook hands down
3D: just started playing