Hey Layne, threadfin should be fine in your pond. I'm working presently with a 60-acre lake that's a little above you in latitude and which had them stocked - along with gizzard shad which you wouldn't want to consider until your bass have put on some size - a few years ago, and they did very well and are still in the lake (as are the gizzard).
Southeast Pond Management sells threadfin shad, as well as golden shiners and crayfish; they also sell tilapia which can be another good forage.
