There have been issues with unknown and missing Airport identifiers in MSFS. Airport information is contained in the AIRAC file distributed to aviation-related businesses and available in MSFS (and others) approximately every month. The information in the AIRAC file comes from various governmental aviation departments such as the FAA in the US.
The 3 airstrips you listed, T16, NM54, and NM16, are in the FAA database, in MSFS, and in Navigraph. All 3 are privately owned by the National Forest Service. Only T16 is a public use airport, open to the public. The other two are private use only. KREV and KRER are only in MSFS.
Navigraph also uses AIRAC as their source file but MSFS and Navigraph process the AIRAC file differently. It appears that when MSFS receives and processes each new AIRAC, it doesn’t remove airports not in AIRAC. Also, I think that ownership transfers and location changes are not processed correctly by MSFS.
A few months ago I had one private airstrip that was in MSFS that had been sold, acquired a new identifier, and then “moved” by the new owner. It took a long time for MSFS to accurately reflect these changes. At one point, both the old and new identifiers were at the same location.
Submit the removal of KREV and KRER to ZenDesk. (This process might change when SU14 is released.) If and when they are removed, maybe the other information eventually will be updated automatically from AIRAC.