[MM] Could the Happy Mask Salesman be a grown up version of Jim?
I'll start by saying this is an idea I had before bed two nights ago and that all of my "evidence" is mostly circumstantial. Any support or counterpoints to my claim are welcome because I'm not trying to state this as a fact.
There aren't a ton of concrete similarities between the two, but I believe the two most important are that both have a proclivity to make people happy and that their hair colors are the same. A handful of other character have similar hair colors, but I personally feel like these two (and the other bombers) are closer to each other than anyone else withe same light brown/orangish colored hair.
Another small quirk is that In the N64 version of the game you get the Bombers notebook from Jim, while in the 3DS version of the game you get it from the Happy Mask Salesman.
My "big idea" is that Jim somehow survived the events of MM in a world where Link didn't intervene, or at least any time link fails to stop the moon from crashing. The trauma drives him somewhat mad and obsessed with masks, now believing that he can save his home if he goes back in time and finds the Mask that caused it; unwittingly causing the events of the game in the first place when Majora's Mask is taken from him by skull kid. It's another time loop surrounding Link's time loop that causes the events of the game to happen over and over again.