If there is one thing that Trumpers try to do it is contrive bureaucratic red tape to obstruct an America's right to vote, despite being unable to concoct anything to contradict the reality that voter fraud is extremely rare, and cannot be shown to have ever altered an election's outcome.
If you want to try to pervert the results of an election, pressure voting officials to "find" your needed votes, try fake elector schemes, incite goons to attack Congress. Even then, you'll fail.
Should a convicted felon be allowed to vote by mail if his state law permits it? I think so.