Talkgroup 2352 is also used by some troopers in Union County / H-3.
According to RR, the Charlotte Fire "regroup" talkgroups are 18384, 18416, 18448, 18480 and 18512 ... and 18544 is the unit locator talkgroup. Based on your post, Darned, you might be missing regroup channels 1 and 2.
There is a similar set for CMPD. It would be more-likely that NCHP would end up on those regroup TGs during a multi-agency incident.
If you don't already monitor them, the IMAP talkgroup (3536) can sometimes give you an early heads-up on traffic incidents that Highway Patrol in getting ready to dispatch.
I would also monitor the law enforcement mutual aid TG (2064), as there is some intercommunication between NCHP units and CMPD on that TG.
Jeff Multer