I've personally investigated that after converting my certificates, but get a job as a CPL is very hard, with M-1 you might get some non-aviation related jobs.... J-1 is better but only for Ab-Initio, that means you get the J-1 only i f you buy the whole training, and is issued by some select Flight Schools only, and once you finish training you get 18 months to get practical experience (commonly FI), but not allowed in M-1
Mostly no one, specially in the US aviation industry will hire someone with papers out of line.
Basically the only chance to get a Pilot Job in US not being a citizen, is the (un)famous Green Card...