I think we can add some more stuff to your assumption list, @InaneFool.
Lots of characters to care about, most of them are going to die repeatedly due to what may seem simple on the surface, but is really complex once unraveled.
Bern and Lambda, or some sort of piece equivelant of them. Possibly (Umineko Spoilers) Featherine may come back as well. Or a piece to represent her.
Potentially an abusive character/abused character.
Themes of having to overcome something really hard, and it taking a miracle to do so.
A theoretical miracle world that will allow us to see the antagonist (or an antagonist) as human.
As for what animal will be crying? I dunno. I like the idea @Yerian has about lambs. I think it’s be super interesting if WTC3 was a inspired by Silence of the Lambs, like Umineko was inspired by And Then There Where None. I for one think that would make a very interesting story…