Propper has the current US Air Force uniform contract for utility uniforms. That means that via
normal channels, i.e. uniform clothing store on base, it would be a Propper multicam uniform worn by a PJ. However local commanders have the ability to dictate local uniform policy, especially for deployed units. So you can see a lot of different uniform types. I don't think you would see the Atlanco TRU because it is really the same thing as the Propper uniform. You will see a mix of other multicam gear - Crye, Beyond Tactical, etc. And there are a lot more vying for those smaller, local uniform contracts. Massif makes the "authorized" Air Force multicam combat shirt--oddly only for enlisted--what about us officers?

, but it has the crew neck collar, so you will also see zip up types (Crye, etc.) with the full collar in use to protect the neck from vest collars and slings. Even when not purchased by a unit, deployed airmen will purchase clothing on their own if it is more comfortable for a deployment. National Guard (State controlled) units have even more leeway.
We have Beyond making samples of the ABU (Air Force tigerstripe) in their L9 pant with Crye knee pads for CONUS SP (Security Police) and SS (Security Specialist) units. We wanted Crye to do it but they are so backed up with multicam production we could not have even gotten a sample in a reasonable amount of time.
By the way the issue Air Force sidearm is indeed the M9. I do not personally know if a unit commander has leeway on that policy. But when deployed with a Army unit it is normally acceptable to be able to wear and carry what that unit does.