Now that I've had some sleep...Camp Shelby range control IS still on 142.325 (210.7), as well as some low band freq I cannot recall. They also simulcast that on MSWIN on the two sites at Shelby.
There are at least 3 other VHF freqs in use there, for public works-type traffic, etc. Everything else is solely on MSWIN...Fire, security, constables, training, etc.
FYI the NG Youth Challenge Program no longer uses the UHF freq listed as them in the DB, so drop that one from your scan lists, and you can also drop Hagler Airfield since it's been 99% decommissioned except the ramp area (which is the drone base) and very sparse helo activity during AT.