Given that DD's calling card has been edge rusher, I think the texans are just throwing another into the OLB mix despite his lack of traditional size. Out of the group of Dunn, S. Orr, R. Orr, Anderson, or Acholou, I expecting the guy who is the best special teamer to make the 53 man squad with one maybe two of these guys on the practice squad.
As for the LBs in general, the top 5 appear to be Babin, sharper, Peek, wong, and Foreman. Wong seems to the most verstitle and will move around if need because of injury.
Also, becuase of Wong's ability to move around that may mean the team only keeps Evans or Polk, not both, which may give another OLB trainee a chance at the 53.