It's obviously well fed and groomed

I don't actually disagree with you, but in the case of stray cats, this is actually a bad indicator. Many strays are very well taken care of by their local community. My neighborhood, for example, maintains a cat colony of about 5 cats. They're well fed, and if you just go by their coat you'd assume they get taken to a groomer weekly. They just eat well and take care of themselves, though