If the NJICS control channel is strong, then you should be able to decode it with the SDS100 at the very least. I don't know why you are having so much trouble doing so. I would try to really simplify your programming for troubleshooting.
Create a new favorite list, add one P25 Trunk system to it (not X2-TDMA), add one site to that system, then add only the active control channel. Go back to the system options, and turn ID: Search on. That's all, don't bother with anything else at this point. Turn every other favorite list off in the scanner and see if it start decoding activity.