Transferring my licensed work to another account

Go to that new account immediately. Changing later on won't be that easy.

If you are currently on a Teams or Enterprise account, anyhow, it won't be possible to get a contributor account. What @Test Screen Name says is correct, even that there is a possibility also as a business with more than one photographer/artist to contribute. But the general rule is one photographer, one account.

No, I don't think so. I suggest you set up a completely separate account to manage your stock photography. Never use a business email, since the contract is an arrangement between Adobe and one photographer, not their employer. It doesn't have to be the same as a subscription ID. (At least, I think that's a good idea, let's hear if there is any reason against it).