This one is kinda my favorite but I will start with Mike as he deserves some attention and less suicidal content of him.

I feel like after the bite he could've grown to being afraid of being watched and having eyes all over him glaring at him and his dumb choice.  So Scopophobia, I feel its possible he could've grown to being afraid of the dead kids knowing what they can and will do if disturbed  or angered. Necrophobia
I don't think his fear of the kids would be extreme like his dad's  but he would still help get the kids free from the suits and get the  peace and freedom they deserve. 

Evan
I personally feel he's a shy 9-12 year old that has the mentality of a small kid(4-6)  while his emotional health is at the edge of the  cliff.
I think two of his fears are darkness Nyctophobia, which is thanks to the nightmares and part of  his process to slowly growing up, pediophobia dolls, 

he doesn't interact or call Plushtrap one of his friends and was silent when his Fredbear plush asked if Evan still believed they were his friends. I feel after he died or while he was suffering he could've had stomaphobia especially when the nightmares did admit to fueling on fear. He did show quite the disliking of being trapped in his room, trapped in the back room  before he started crying again cleithrophobia being trapped.

Elizabeth

I can list a few off the bat if she honestly survived and was removed from Baby's storage tank she would have extreme coulrophobia, claustrophobia, and pagotophobia. She was quite the germaphobe in the books and would cleanse her hands over and over as she prepared to do William's surgery.  Thanks to her father she also seems to have Atchiphobia  fear of failure and does everything she can to please him and not let him down.

William
Honestly he deserved being seriously scared of the kids coming back at him he stole their futures/dreams, caused them agony, and humiliation.
He's quite the control freak the minute he sees he's lost control, he has a fit in a half or starts freaking out.   I feel he has Phasmaphobia  fear of ghosts

Mrs Afton
There's not really anything to say about her as we don't really know too much about her.  Other than what her appearance and supposed behavior to William. From the show.