So yes, the police are prohibited from stopping a vehicle based solely on the knowledge the owner has a suspended license IF it is obvious the driver is not the registered owner. The police need reasonable suspicion a crime is being committed to make a lawful stop. In the scenario you describe, as long as it is clear the driver is not the owner, there is no reasonable suspicion to effect a stop.
and using your basis for a stop, that would allow the police to stop any vehicle where the driver’s appearance doesn’t match the registered owners description simply because it isn’t the registered owner driving the car. That would allow them to stop even something such as you allow your husband to drive your car that is registered only In your name. Don’t you think that would be a problem? Where is the reasonable suspicion of a crime that is required to stop the car?