In terms of colours for Exegol, I’m firmly in the camp of:
- A greyscale planet, with no tint, to imply absolute lifelessness
- Non-green fluid for the clones (either red for the nice contrast, or we make as much as possible of this tech look Kaminoan), to clash with the later green
- Green mists around the throne, as it’s a nice alien colour we’ve not had in a finale for a while, both evil and not just sith-red, and also as a bonus hints at the Nightsister connection for those that care.
I really like all of these ideas! Well, the latter two anyway - the greyscale planet I’d have to see in action.