If you got the scene with Claire in the basement, then after midnight you can meet Bianca (near where Tia is during the day), She'll teach you lockpicking.
As for ntr with Thomas, I never did it, but I think you don't interrupt their chat at midnight and you don't tell him your a couple.
Evangelion is right: She must dance for you, then you can give her wine, to make her sleep while you spend time with her mother then look for a new dress, then you decide : Only for your benefit or during work roll on "NTR"