I'd take Johnson over Jeanette and Mcvey. Why? Because on film they don't overly impress me. Johnson can even be a little hit and miss on some film for me but I can see more signs of elite level craft with him at times. Johnson vs Langford is tough to call. I'll let someone with more expertise on these two decide. Langford could punch but Johnson had the size advantage. Good fight.
I'm going with the above. From what I've seen of johnson and seen of mcvey and nette I'll have to choose jj. Langford, from what I've read had a decent thump. Depending on how johnson comes in to the fight and serious he takes it, then johnson wins a decision. But if he plays around and doesn't respect his opponent, then Langford could land a good one. Could be a surprise upset. Nette and mcvey take him the distance but lose decision s.