I didn't extensively test but these are just added as empire modifiers, so I suspect there shouldn't be many desyncing issues.

@Duckpower2017
That wasn't outlined when I asked, but thank you for pointing to it.
It would make a great enahancement for MP games, but I fear the different levels for each player may result in desync quite often. Tests will tell.

@Kepos it says each player gets to choose a difficulty, so if each player gets to choose a difficulty it would be reasonable to assume that difficulty is seperate to each player and they get to choose their prefered difficulty at game start

You might want to give some more details. So far I understand, the host gives each player a ranking or chooses every player by himself?