You can do that using game rules before starting the game.
Nuclear war is the only thing that can be disabled mid-game. For that you need to type "debug" in console and find necessary decision.

This submod will continue developing and will try to adapt with new Germany lore.

Some flavor content, like events, national spirits regarding them - yes.
Complete focus trees and possibility to play them - no.

More likely yes, than no. We have some plans regarding it.

No, but you will have reduced timer to invade it. If/when the timer runs out - USA/Japan will declare war on you.

You can always join our team through applications[docs.google.com].

Maybe. However 2WRW is unnecessary for this submod since, usually, Germany executes Fall Rot much earlier than 2WRW focuses unlock.