Thanks everyone, this is excellent advice.
I opened the closet door in the kitty room and made William a really nice hiding space in there. He is now sleeping there during the day and is comfortable. I have his food and water in there too, so he feels safe.
He does love the room for wandering and yesterday I put a bedside table level with the window and anchored some cardboard scratching boards there, and last night he sat there as well as part of today, crying some of the time and just resting otherwise. I have not done the music but that is great advice and I will do it.
The last two nights I've gotten up and gone to bed in his room when I've heard him crying. The first night he climbed onto the bed, crying the whole time so I would know where he was. He did not stay on it the first night.
But last night he not only stayed on it, he curled up beside me
! Also when I rolled sideways (after I couldn't stay still one more minute!) he simply readjusted himself too.
I still cannot touch him. It is so strange because he does lay with me and wants to be close but touching is alien to him. Right now anyhow it is practically impossibly to touch his face or neck with the collar on, and given his tail amputation, there is not much I can touch on his back area without probably causing him pain. But I will try very slowly over time when he begins to show signs of feeling better.
Believe it or not, the vet did not give me ANY pain medication for him. So I am just putting the antibiotics in pill pockets. I was really wondering how they could not give him pain pills and I was thinking he was probably in pain. I really don't understand that.
On the e-collar, you are absolutely right MOM: the vet said he thought long and hard about putting it on a feral cat and told us to bring him in if we needed help getting it off. He said there was a chance we could get it off ourselves. He concurred that William is fearful but does not show it in aggression.
Ace is doing ok but not thrilled. I do believe she is grieving a little bit. William heard her crying for food and attention - and probably him- this morning when I fed her, and he started crying too. Unfortunately,(or maybe fortunately), his room is in the front of our house and their hangout is in the back. I think she is hanging on right now because of our cats and because we play with her and talk to her through the door. And in the mornings I let her in the house and leave the door open while my cats are locked up. I started doing it for them this winter when it was so cold. I think that is why William is not throwing himself against the walls right now actually.
I think Ace and William would be always fearful but ok with us indoors. I've been playing with them and all our cats (through the screen door) with toys for about a month now in the mornings and evenings.
The main reason we would socialize them is in case we move, we would need them to come with us. Also they are just a colony of 2 and neither one of them is aggressive. Plus we have raccoons, other un-neutered cats, possums, and all kinds of critters outside and these guys are such babies we worry constantly that they will succumb to an outside bully critter or person.
I'm more worried about my cats. None of them are dominant but there are 4 of them and I really worry that I may push them over the edge adding two more to the household- especially adding William to my other male cat, Toby.
Anyhow, good advice to take this up in another thread. For now I will focus on getting William well.