That is a very astute observation and I am inclined to agree that this is the most likely of all possibilities.

According to an article on IGN, Aunoma states," The new Breath of the Wild or the sequel to it, it's not necesarily going to be related to Majora's Mask or inspired by it...What we showed you currently is a little darker."

majora's mask was one of the first games I got into as a kid and breath of the wild looked great, I might get a switch for this if its a sequel

Aonuma can say whatever he wants about Majora's Mask not being an inspiration or even a factor that's playing into this game's development, I'm not buying it one single bit. It's painfully obvious that the strategy and thought process behind developing this game is extremely similar to the strategy and thought process behind Majora's Mask: A darker, edgier sequel which takes place immediately after its predecessor that reuses the assets and engine already built and aims to perfect them while doing something on its own to stand out as an amazing game in its own right. It's almost 1:1, the development and foundation behind Majora's Mask. But hey, not that I'm complaining. Majora's Mask is the best classic-styled 3D Zelda game, in my view. So taking notes and drawings from its development is already a big plus for me!

When I refer to MM, I am speaking as to how they got it out so soon.  Reused assets such as character models and engine, and all that jaz.  It has nothing to do with the theme or plot what so ever.  That is not to say it cannot go that route (personally I am leaning no, as I believe the corpse is most likely Ganondorf), but that is a different topic.

I definitely agree when speaking about this sequel being cut from the same cloth development wise as MM. This thread originally began as a "proof" that it was a MM sequel. My quote fron Aunoma was just adding to the growing support that it isn't a Majora's Mask sequel. It definitely uses the same assets and engine and will release soon, so in that respect I understand the comparisson. And definitely way darker.

Sorry to dissapoint you, but Eiji Aonuma has already confirmed that this game has no connection to MM.

https://www.ign.com/articles/2019/06/11/zelda-breath-of-the-wild-sequel-is-not-related-to-majoras-mask

That artifact that you referred to is actually the Gerudo symbol. It has nothing to do with Majora's Mask.

I hope not, let it be its own animal geez

That music in reverse sounds like the great fairy theme to me... could that be the hand of the great fairy reaching out to him... did anyone check ganon's body to see if he had a bottled fairy? come on guys you need to loot the bodies properly!

Also the body is wearing Calamity Ganon's headpiece from the end of Breath of the Wild