While there have been a couple 3some events, there hasn't really been any indication of a harem capability. There's still material to uncover involving the MC's mother (Cassandra), how they deal with Cornell (the conniving uncle), Lori losing her virginity (if you've chosen that route), Barbara's issues with the event at Daphne's house (if you chose to complete it), and lots of Daphne issues, which may open it up. My guess is that at some point it'll come down to selecting one, or maybe two, of the girls but a complete harem won't be on the table.
As for Love vs. Lust, I know that prior to .8 someone had a game mod to modify (add or subtract) both point systems. It seems that release .8 no longer used the point system and went to something more akin to flags, or triggers. Early on it was important to stay on one path otherwise you didn't gain enough points to trigger special events with the best scenes. Sometimes missing one, means you miss a whole series (sex with Julia in the shower, sleeping with her, sex in the morning). I'd recommend staying the coarse of either all Lust or Love and not mixing them on any particular girl.