I’m curious. Items are lost for ever?
Lost? I presume you have them saved locally on your computer? But yes, they will be removed from the marketplace if you close your account. Remember that you can’t re-upload the same items again if you change your mind.
I’m not sure if there’s an option to delete the account. You could contact the support and they may disable it but pretty sure they won’t delete it
Yes. You can close your account and have it removed.