Yeah. I have no doubt it'd be much easier now.
Let's see, I actually have my copy, so I'm able to see exactly which ones brother and I were able to do as kids:
Bonkers, Rocky, Tac, Plasma Wisp, and Chilly. It was basically the spectacular defensive stuff, plus Bonkers (for obvious reasons - THWACK), minus Mirror (because it was too short ranged and weak, even with the mirror dash).
I just put MK Ultra as easier because... well, one unlucky death doesn't end it, and because you have the all important Heal.