If only the owner of the copyright can claim infringement (as is the case in the US), then the point is moot. Is J. Doe going to sue herself for violating a license by releasing under another license?
One can contractually agree to make some else the exclusive source for something while retaining the copyright. In which case, if you then offer it to someone else then that "exclusive" party can sue you for breach of contract. Of course this has nothing to do with any of the open source or CC licenses.
> If only the owner of the copyright can claim infringement (as is the case in the US), then the point is moot.
An exclusive license is a transfer of those rights under copyright to which it is exclusive from the licensor to the licensee. So the licensee would be, for the rights in question, the copyright holder, even if they were not the creator and the holder of the remainder of rights under copyright (see 17 USC Sec. 101, 201).
Kind of. More that individual rights can have ownership transferred too, separately from each other and the original copyright, and any owner of the rights can claim infringement of the rights they own.