Ok, After Rinny get captured by that mirror event: visit pixie.
Then, after the confrontation with pixie, choose the attire that match the gender (male get butler outfit, and vice versa) otherwise you get detected nonetheless (unlike the original Lust Doll, where that choice doesnt matter)
Gather all the outfit after that, confront that maid on the corner to the right of second floor of manor, win the fight.
Complete the manor quest as normal after that. Once the quest done, confront that same maid in the corner to the right of second floor, there's the Marin event, experiment with all choice (Make save point just to test all the event)