Did some more investigations. These were my results:
GOOD STYLE (mid P & mid K)
-Hayabusa
-Ayane
-Hitomi
-Bass
GOOD STYLE (mid P or mid K)
-Phase 4
-Hayate
-Rig
-Tina
-Mila
BAD STYLE (mid P & mid K)
-Marie Rose
-Leifang
-Bayman
Then there's Kasumi, who is in a category of her own. Her expert mid P hold works well (Hayabusa-style), but her expert mid K hold is borked (Marie-style). It's not as disastrous for her, however, as the command it gives you is her 43H mid parry rather than an expert low hold. Thus, if you were trying to hold a mid K, you'll still beat the mid kick, it will just be with a different move.