Skipping the lesbian voyeurism scene here means also skipping an opportunity to gain an
ovidius_influence point. No idea if those will have any significance yet.
Does the first meeting of Euphemia work as intendit? I refused to accompany her home and the game completely ignored it and proceeded in to the scene of MC leaving with her.
You're right. The variable
eu is automatically set to true when leaving the bar regardless, and is then checked immediately and repeatedly after that to see if it's true: If true then the MC is with her. And then the story automatically goes on to her place after the fight, without checking any variables at all.
None of the choices you make when meeting her in the bar affect anything.
If the MC rejects the slave from Marcus, the next morning she'll still be there when Marcus' men kick the door down.
The game then ends immediately after.