Transporting? Maybe. Manufacturing? Nope. He has the right to do so.
No. Manufacturing NFA items without a completed and approved form 1 is a felony. IIRC most NFA items also need ATF preapproval before crossing state lines. This was Bad Idea City.
Yeah, but those are unconstitutional laws to begin with. Feds are probably smart to let this go, least they end up with a new Supreme Court precedent.