Eric scenes are not really for me, more power for the dev in implementing them, but I'll avoid it completely.
At the original even the scene with Eric massaging Alice bothered me, but I discovered that if you never start the conversation about her blog he will never touch her, and to avoid Lisa sex ed you just need to not choose a Lisa path, them you avoid Eric completely, he would only fuck Kira since it's a required event for you to get rid of him, Ann obviously, and jerk off at the corridor for Alice I guess.
Didn't mind his scenes with Ann and Kira, he is Ann's boyfriend, so whatever, and Kira is Kira, she at least was being blackmailed, not really being corrupted by him like the sisters are