Yeah, Snoke being the Sith Cult leader would actually be great and give him the backstory that he was lacking in TFA.

I figure the dyad would be something that is independent of the Sith plans, regardless of the edit since it was that way in the original. If anyone has a better idea I’m open to it, though.

The life force drain effect could flow from the Sith Cultists in the arena towards Palpatine as a sort of constant, barely perceptible effect in a couple shots throughout the film. I imagine that their combined Force suffices to power the crystal and the Palpatine illusion. That way the Force drain becomes an organic part of the operation of the crystal instead of a tacked-on ability like in the original film.