My solution is just one of tons that have been proposed here but it would be essentially:
Losing facility-
-Has bodies for a release, rank everyone by time CPC at their CURRENT facility only
-Take stock of all ERR's, find the ERR to a facility with a vacancy of the most senior (at their current facility, not NATCA seniority) person, award them the release
Gaining facility-
-Vacancy exists, sort all inbound ERR's by the controller's time at the facility they're coming from, award the transfer to the person with the most time
If the CPC transfers and certifies, everyones happy. If the CPC washes, they go straight back to where they came from and their facility time starts over
IMO would be by far the most fair system. Eventually everyone would get the chance to transfer, and no managers picking favorites