I'm not so sure anymore I even need the incest mod, as soon as I reached the part where Elaine was introduced I was so smitten by her I forgot I was playing the incest mod for Monica, Katie, Jenna. For some reason it felt more taboo pursuing Elaine so I ended up focusing on her instead of my 'family' which is supposed to be why I installed the mod in the first place.
Maybe it's because I subconsciously know they're just modded to be your family. I didn't knew about Elaine beforehand, and now I just ended up pursuing her instead which defeats the mod's purpose lol.