This is sufficiently complicated I'm going to get some of it wrong...
In a nutshell...
KXZK was first authorized as a Lordsburg, New Mexico station on 103.7. Before going on the air, they got the permit amended to move the station to Vail. They went on the air from a site southeast of the Vail exit 281 off I-10. The current permit moves the station to 104.5 and a new transmitter between Vail and I-10, about a mile southeast of the Colossal Cave Road exit #279.
KRDX was first authorized on 98.3 in Nogales. They moved to Vail and changed frequency to 98.5 in 2002, then moved again to 104.5 at Corona de Tucson in 2007. Now, they have a permit to take over the KXZK transmitter. (with a slight increase in power)
KWCX-FM is not related to the other two applications. It was first authorized in Willcox on 98.3. They moved to 104.9 in 1997, then received their current permit to move to Tanque Verde.
As for the translator... it's a secondary service. If there are any complaints of the translator interfering with KWCX, the translator is required to make technical changes (change frequency) to eliminate the interference. Either that, or the translator goes off the air.