I just finished that yesterday in fact with a lvl 30, 900+FS Understudy Cerebella. She had 2 Merry Gorillas equipped and 3 Blockbusters. (Dynamite Dynamo, Diamond Drop and Diamonds are Forever) Basically you must block every attack they do and properly throw tech any throw as well as having decent combos so you can kill them before they chip through your blocks. Also gotta hope they don't have an unblockable, those are really stupid when they appear on enemies that are supposed to severely outmatch you. That's the problem with random move sets I suppose.
Merry Gorilla (It's the special move that grabs somewhat distant enemies and does a spin) is a nice move because it can be immediately used after Cerebella's Ground Combo (unless they're cornered and not Big Band) and you can initiate another Ground Combo. (Doesn't work on Parasoul, also only 2 Merry Gorillas per combo) Another alternative is to use a Big Band (preferably Beatbox Big Band) because he has really high combo potential thanks to Cymbal Clash's stun.