One small point… “There is a remote starter, but you have to be where you can see or hear the car to know if it has started. As we get more forgetful I worry about the lack of such a feature as forgetting a car is running in a confined area is a potential health hazard.”
I sell Cadillac for a living and am well versed in the remote start function on the CTS / STS. When you perform a remote start a 10 minute timer starts. Forget about the car and it shuts off in 10 minutes. Also a health hazard for any length of time in a confined space is debatable as the CTS and STS (and most new cars) emit very little hazardous gases compared with cars of yesteryear.