After writing the previous update, one of their representatives stated that I had come to an agreement with their GM. That was inaccurate. Their GM agreed to replace the missing SD card, stating that it was the likely cause of my issues with the backup camera.
The SD card was replaced, and for the first time my navigation system worked. A Carfax report revealed that this vehicle had been stolen and the previous owner returned it to the dealership shortly after its recovery, after which Camelback Toyota resold it as a Certified Toyota vehicle even though the SD card had been removed (likely by the thieves to prevent tracking of the vehicle).
Furthermore, the backup camera stopped working for 3 days AFTER they installed the missing SD card, so the problem is still ongoing. However, I will not be returning to Camelback and I warn others to stay away from them too. (See previous update for the background on this story of lies and deception on Camelback Toyota's part!)