Welcome!!

First, no cat can stand closed doors - NO CAT.
Second, your cat is displaying some typical feral behavior; reaction to sudden movement and noise, hiding under the bed, eating only when there's no light and no one watching...
This shall pass. You need to give the kitty time and let him come to you on his own terms. If you try and force anything you'll get resistance and a lack of trust. Let nature take it's course, and you'll both be fine. Good luck!