CCL,

You have to do what is best for you & your fur family.

I don't blame you for having concerns about Mr Magoo with your fur kids, because of what happened recently.

But I also agree with Johanna, that he needs to be placed in a spare room for some time before being allowed to intergrate with other cats, in his furever home.

But this is impossible at your home because of the layout etc.

I do think he could live with other cats but he needs more time to settle than most cats.

Though from your description I think his biting is more fighting to be top cat than real aggression. Which is good new for his next home.

It is better that he goes back to spends more time at the shelter, than to stay at your home when you & your kitties are uncomfortable with him.

Good Luck with your wrist getting better and Mr Magoo finding his furever home very soon.