1. Vinnie at the Victory Hotel. Solved by Sunbeam's trainer. (Kill and forget.) He always manages to kill her when I fight him, despite my being able to soundly defeat everyone else in the game. And when I try to sneak past him without alerting him to my presence, he still abandons his pizza, comes upstairs, and manages to head directly for where I'm standing. So annoying, but not any more thanks to Sunbeam.
2. Grubbers in necropolis caves. Solved by Sunbeam's trainer. (Kill Warrior Grubber, break grubber script, explore at leisure.) April's somewhat clunky hiding mechanism combined with grubber noses made for a very frustrating time in this map. Killing the Warrior Grubber prevents the script from summoning more grubbers.
3. The crumbling stairs in the final necropolis region won't crumble for April if she's in combat mode. The problem is she can be at the trigger point and the Warrior Grubber can be off the steps and the script still won't trigger. It's frustrating, and happened to me the first time I played. (Now that I know about it, I'm careful to get a running start.)
I can't think of a fourth item even if it was allowed. All other fights are really easy, and ZŲe's hiding mechanism seems to work better than April's (maybe because she's standing instead of crouching).