I wonder if the person in the stolen photo would also "prefer to limit his recognition as best as possible for his private social life, potential l_w enforcement and/or "potentially" being fired at work." Especially since the person in the photo is, in fact, not the person who placed the ad.
This point alone makes all the other points moot to me. If this "provider" is so lacking in respect for others then why should I believe he wouldn't do something shady to me? This speaks to your question of "ripping off" a client.
Also- I read it three times and still have no idea what you're trying to say about spray on tattoos or whatever.
Lastly, each time you double-down on how good a person this guy is it starts to make me wonder what your real connection is to him. If you're such a fan you should probably let him know what he is doing is not only wrong, it is technically a source of potential legal trouble from both the subject of the photo and the photographer, and he should reconsider the strategy.