Shifter

Probably not having other Keyblade wielders as party members and lack of character development.

Most likely during Dream Drop Distance, the outfit Sora had during the game drew in darkness plus Sora remembering Aqua and Terra. THere's also the matter of Ven's heart that may also be part of the trigger for Vanitas to revive.

Not sure but since we see the other members of the original 13 making an appearance maybe one of them? Also someone posted a what looked like a trailer for 100 Acre Woods for KH3 but it might be fake.

Can't be since she met Ansem after KH2 events.

Makes sense although it wouldn't surprise me if the Master of Masters does a Kagura from Naruto and revive himself.

Aqua a Seeker of Darkness? Interesting.

There are a few Anime series that I could see appearing in Kingdom Hearts 3. Soul Eater and Bleach being two of them. Sword Art Online being another. What do you think? Do you see a possibility of Anime in Kingdom Hearts, and if so which series and why?

There are a few Anime series that I could see appearing in Kingdom Hearts 3. Soul Eater and Bleach being two of them. Sword Art Online being another. What do you think? Do you see a possibility of Anime in Kingdom Hearts, and if so which series and why?

Sora and Mickey tried to merge their Kingdom Keys together?

Something came to mind while looking at the different trailers and the games, and that is the similarity a few of the worlds have to Daybreak Town. This is a complete theory here but some of the locations that we have been to so far have had city based structures. Looking at these locations: Land of Departure, Radiant Garden, Traverse Town, and Twilight Town I have seen similar structures in the Daybreak Town images we have seen so far. So here is the theory: these worlds were once connected to the Keyblade Graveyard but from the Keyblade War, they got separated into these different worlds. I may be wrong on the theory but the looks of the locations make it seem plausible. Opinions are welcomed.

You may have something there, a theory did come to mind though. What if the Foretellers that did survive are in either the realm of sleep or darkness.

The only other thing that would make sense is if the Master of Masters if the theory holds true is if he possesed Xehanort. I mean how do you think the Organization 13 black coats appeared.
 
I may be off on this but as mentioned above Yen Sid knew about Eraqus and Xehanort from apprenticehood. The MoM couldn't be their Master. The trailer for KH3 shows Xehanort's eyes being different.