From everything I remember and have read about the standoff, the ATF and FBI along with Janet Reno’s Justice Department ran the entire operation. If the locals were involved it is pretty certain it was on the extreme periphery.
So it is pretty likely he was not involved.
No, they weren't. Local law enforcement (the sheriff, I think) knew Koresh well -- well enough that he could have walked up, knocked on the door, and asked Koresh if he could inspect any firearm he had. Koresh would have complied, because he had done so on at least one previous occasion.
But, the ATF was so intent on doing a high-profile operation, they went in with massive force.