.....but he said that I would be leading the ROTC with the PT. If I do get into this program, am I required to lead the ROTC instead of attending reserves?
Nobody in PLC leads "the ROTC", nor does any sort of newbie in the NROTC program. If you did choose to participate in NROTC and earn your commission and air contract there, you would eventually work your way up to more senior levels of "leadership" along with increasing weekly time commitments. That said, at my old unit some of the PLC dudes did PT with our Marines though they were in a completely different chain of command.