@captain stone
I think those street agents would be in competition with the likes of Wilson, Harmon, Gregory. As much as that trio leaves a lot to be desired I doubt there's much better on the open market than they are. No one is going to cut any of their safeties than can cover which is what the Patriots need next to McCourty until Harmon develops.
As it relates to Ebner, if you're signing a safety to replace him then it would be as a strict ST-only guy which is what Ebner is at this point. I doubt you're going to find any safeties on the open market that are better than Ebner on STs.
The Patriots seem to be done making cuts in the DB group. The only thing I envision them doing is adding depth to the CB corps with a CB that can defend a pass