I can’t see how the stop/taillight could affect the cruise control, but you could remove the bulb you replaced and see if the cruise then works. If it does then that’s a pointer to the cause of the malfunction. To be sure take it to a dealer or an auto elec and have the problem traced.

Both the CX-5 and the Tribeca are good choices; they're capable, well built and reliable. Others to consider are the Kia Sportage and Sorento. While they are Korean like the Captiva, unlike the Captiva they're very good cars, well built and reliable.

When Subaru updated the Transmission Control Module in 2010 it did what it thought was needed to fix the problem, but clearly they discovered later that the problem was with the torque converter. All of that suggests the company was being helpful in trying to fix the problem. Now they are offering you a new torque converter, leaving you to pay the cost of fitting it. That's a fairly standard deal with a car as old as your daughter and son-in-law's, and I would accept it.