Have my two cents:
I think it is very rare in this brand of theorizing that people believe anything is "literally" the case. Like I don't think Mattpat or anyone who developed the Link dead theory actually downright believes that the game you're playing is from the perspective of a dead kid with a mask fetish or that the developers were intentionally creating this game from that perspective. Anymore than say....A A Milne intended Winnie the Pooh to be read as an allegory for mental illness or that Harry Potter is mentally ill.
That isn't to say that creators don't leave little things around for observant audiences to notice, just that it isn't usually as firm as "this is what is actually going on".
I also think this happens a lot, to be honest, because cliches are quite broad, allegories are broad, almost everything can be read using the bible, the divine comedy, or any number of psychological readings because we're taking the broad strokes of each of those topics. And I don't see anything inherently wrong with any of that. I think it is a lot of fun to see the Matrix and get a biblical reading out of it. I think it is very hilarious to see Harry Potter's grand quest and life as the product of a disturbed mind. I think that looking at a game like Majora's Mask and seeing him as dead lends itself to some semi-interesting explorations.
I also don't, to be very post-modern, think it matters much if it is literally true. If you play Majora's Mask after losing someone or something, and see those themes, and get something significant from it, I don't see it much being of interest to know if the creator intended it, the point is that you got it and it made the experience that much richer for you.
But if you're really set on knowing if it was intentional or if you got the sign you were supposed to, I am sorry to say I do not think so. Loss and grieving death is a very common theme in art. Without taking any psychological decoding of how grief works, I think it is very common for people to be sad, angry, bargain, etc. without you needing to have that very academic perspective of it.
I mean, I've never cared much for Majora's Mask, but it's just as easy to read the "terrible fate" that Link has met with as being the fate of heroism. I think the game can just as easily be seen as this sort of in depth exploration on the darkness that comes with having the weight of the world (or moon) on your shoulders and the things you come across if you're acting in a heroic capacity (the loss, pain, and death often inherent to the hero's quest). I'm not saying that's what the creators intended, but I am saying I can get that from it without too much of a mental gymnastic.