When he gives you a key to his place, then you might consider giving him a key to your place/space. He wants a key so that he feels that he still has control over the situation and he can come and go and you couldn't stop him.
I think you did the right thing by requesting a list of items he wants from the home. Be sure you keep a copy of the list for future reference, if need be.
As for working together, I don't see how a key is going to do that. He's gaslighting you and trying to manipulate you into giving him that key. Don't do it. You could very easily come home one day and all of the "good" things would be gone and you would not have a leg to stand on in getting them back into the home.
I wouldn't share anything w/him with regards to the bank account you've set up. This is your account and he doesn't need access to it. He can check the joint account himself and figure things out. Don't share this account info w/him.
Stick to your boundaries and do not back down. This man is all about control and manipulation to get what he wants. You did a nice job of standing up for yourself.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
