Where's the proof which confirms that Termina exists in an alternate reality? Most of the similarities between OoT and MM are down to development time constraints and recycled assets.

The only thing I can think of that could add weight to this argument is the ending sequence where the Skull Kid remarks that 'Link' has the same scent as the kid who taught him a song in the woods. Even this is open to interpretation though. There are many Links and the Skull Kid could merely be referring to the Hylian race. Skull Kids could live for hundreds of years for all we know =P

I have an idea for a Majora's Mask sequel, not a direct sequel, but a sequel nonetheless. I think it could turn out to be one of the most profound Zelda experiences yet if done properly. Check out my thread to see if you agree.