I'd have to see how he performs at HW first before I truly pass judgement, but as it stands, I think he has a solid chance against all of them.
Against Bigfoot, I think he can take him down and do to him exactly what Cain did.
Against Werdum and Mir, I think he can stand on the outside and use his superior speed and reach outbox them, and mix in a few kicks to get the UD.
Against Dos Santos, I think it would be evenly matched in the stand-up department, but in the later rds, I think Jones would get the takedowns he would need to get the UD.
Cain and Cormier are where the true question marks lie in my eyes. Jones CLEARLY has the most dominant wrestling in the LHW division, but despite that, I still think it's impossible to assert where his wrestling stacks up in the HW division, atleast judging from his Light-Heavyweight performances. My guess, is that Jones wrestling would be evenly matched with Cains and Cormiers causing a stalemate and forcing the stand-up. While Jones has the reach advantage, I think they both have the speed to get Jones with some solid shots. Whether I think that will be enough to win the fight against Jones, I'm not sure. But I would assume that those fights would be a true test of how good JBJ really is.