All of this is, of course, irrelevant to the fact that constricting voting is morally reprehensible.
You know as well as I know that enforcing citizenship restriction and single-vote-per-election are critical for a functioning democracy.
Whether or not Republicans are actually achieving these goals is open to interpretation, but attacking the underlying premise is a fool's errand.
Thing is, it's not very credible when the effects of the issues you describe are negligible. That'd be like investing resources in order to come up with ways to reduce traffic congestion in Wyoming.