Money wise I'm sure he takes a hit. I seriously doubt Canelo can fight Lemiuex on PPV and have it sell. I believe he'd have to go on a comeback trail, have a few softer touches and then call up a Spence type fighter. Canelo vs Spence would sell well
Back to Canelo-weight where he brings up WW to 155 or tries to drain MWs? Honestly I think GGG is the only MW of note that Canelo lines up well with from a physical and stylistic standpoint. Jacobs is bigger, stronger, and faster, Dere is more powerful, and BJS has the footwork to dance circles around him. 154 is probably his best shot at regaining glory but if he doesn't have "help" cutting weight, I don't know how effective he'd be.
If 3G wins, I HOPE a 3rd fight will be out of the question, since 3G would have two wins over Canelo. So I assume canelo would look at one of the other belt holders available, or go for whomever is the biggest name available, whether at 160 or 155 for fights.
Depends how he loses, if it's one sided or a stoppage then they have a few problems If Canelo loses and it's a 7-5 type score I would not be surprised if they try and make a third fight, by the time they get around to fighting.. Golovkin will be 54 years old and surely Canelo can beat a 54 year old? Surely?