This might be one good reason to keep copies (though not in a database, rather in a directory outside of mwz to not blow up the backups), if memory serves me well @corey34 suggested/request something like it while ago? Maybe it is a feature that could come in handy for other purposes as well (like recounting or so), as long as it could be switched on/off, then folks would be able to decide if they need it or if they want to afford the speed decrease, what do you think?Mailwizz does not store the actual email that go out, so that won't help you that much.
your best bet is, if you were sending through an external provider, they might keep a copy of the email, otherwise, no chance afaik.
Not sure what you mean, but you can add emails in the blacklist if you want to not send to them anymore.is it possible to submit them bounce emails? bcoz its kind of very important and many email systems run with ATT.