Hard to discuss possibilities when they all remain. I do think the least likely is Jones at 3B. If Jose is traded then I'd guess they view Arias as the heir apparent. I've long thought that Jones would be a damn fine 1B, but I've been convinced that RF is also a real possibility and that would make the best use of his strong arm.
I wouldn't limit Jones' promotion to the 2nd half of the season. I also wouldn't expect him to contribute by then. If he's hitting then get him up here. If he's unimpressive in Columbus then leave him there. Can't know until we know.........ya know.