Seems like they're preparing a new part of Time Temple.

He has this deep hatred of the legends

When did he ever indicate hatred?
Distrust is one thing; hatred is another.

Seeing as he hails from a land that was cursed by the Black Mage after the Heroes failed to save Maple World, I'd be more willing to place my money on that causing his hesitancy to help them.

I don't think Neinheart is the bad guy at all. He is a great commander and all, but I don't belive that he could hide any bad influence under Cygnus AND Shinso, let us not forget that both of them are really strong. Also, I notcied that if Cygnus is the Queen of Maple World, what happened to her parents?

I've never quite understood the whole 'Queen of the Maple World' thing. She's never demonstrated any sort of power or rule over anyone outside Ereve.

The only problem I have with what the Door of the future, is that if it was created by a Black Wings Henchman, then how come Alex nows what conversation I had with him like 10 years before.

The dream could adapt to the memories of those within it.