I'm not questioning FAR91, thats for non-commercial aircraft, in fact, something like the BBJ should be privately operated under FAR125.
As for your comment on FAR135, you are quoting FAR135-2, look at 135-1. However, regardless of the FAR status of the aircraft, what is stopping them from operating it under their own UAE AOC?
I have nothing to do with PJ, and I utterly despise companies who don't pay employees, however if you are going to win your battle, you have to do it right.
Good Luck.
Mutt