In my opinion Vicki might lead to a three way with Nicole and the MC due to the dream that Nicole had. Nicole may turn out to be a closet freak, much like her sister in the end. Shortcake is radioactive in my book, great to have as a side but will ultimately cause you to lose you half sister. So your sis and Vicki are two that I think are safe bets. Those two may be accepted by Nicole in a continuing relationship. Providing that you chose to keep Nicole. If you played Melody as a horn dog you ended up in the tank. Mr Dots in every story he has done that theme runs through it.