Only three left.
27A Nature's role (9) C?A?E?T?R - The only word I can find which fits is CRABEATER, but I'm not convinced.
53A Nervous type of bear around power plant (9,6) T?E?B?I?G ?O?F?R - The first word has to be TREMBLING but I can't parse the clue beyond that.
3D English idiot involved in courses for female parents (14) P?O?E?I?R?S?E? - I think this probably ends in ...ESSES or ...ASSES, but can't get any further. The latter ending would tally with "idiot" in the clue.
Any hints?