I don't think there's anything in OC_PikeInterpreter that assumes anything special about the runtime (whereas Public.ObjectiveC does at this point), so it should be possible to switch out libobjc at will.
What were the specific errors you were getting? I'm travelling, so I don't have access to your past messages on the subject.
Bill
The reason that there is a conflict between libobjc and libFoundation is that libFoundation depends on its own implementation "libobjc.so.lf2" (lf = libFoundation). Why libFoundation can't use the regular libobjc, or why the special lf version don't work as a drop-in replacement, I don't know.