Lowrie's spot really depends on how the 2B candidates play in ST and early in the season. If all of them struggle, Lowrie will probably man 2B. If one of them emerges as a solid option, or a potentially profitable platoon reveals itself, I think Lowrie plays third a lot of the time. His positional flexibility helps them a great deal.
I don't really see Moss playing full time in the wake of this trade. It may even be Lowrie making the most starts vs. LHP at 1B while mixing in at the other positions vs. RHP.
I don't think Wallace is going to play any 3B in Houston. He and Carter may split time at 1B or DH, with Pena taking the other spot, and the Carter may also get a little work in the OF.
Greene should be able to beat out Marwin Gonzalez for the SS job, but watch our for Jake Elmore, who was picked up off waivers from the D-backs. He posted a .344/.442/.465 line in his first exposure to Triple-A last season, which was his age-25 year. He has more walks than Ks in his minor league career and could also give Houston another base-stealer as they try to manufacture runs.