It's been a long while since I wrote the OHS, so my memory of how it worked internally is a bit faded and I don't have access to it on this machine so I can't look it up but I'll try to answer your question.
Spawning the linkboy, and a lot of other things, is controlled by the defauIt player heartbeat script. Any other system that messes with this is going to break the OHS totally. It would certainly be possible to spawn a linkboy with a console command (the resref you would need is ohs_linkboy), but if the default script has been overridden by the one from some other package, the OHS won't function.
Basically, PRC is incompatible with OHS.