53 is "State TAC." It used as a Tac channel by NYSP. I thought I had submitted it to the DB but I guess not. I'll have to remember to do that.
93 appears to be Onondaga Co 911. I have heard them talking about Radio/CAD upgrades before on 93. Not sure if its just for Technical Services or all 911 Administration. I have only ever heard traffic on it once.
It certainly could be. I believe most of the units I have seen on that on that TG don't seem to show up on any of the MRD dispatch channel much and all seem to be OCSO. I think I had seen some city units on there before as well.