Psycho Noriko Route, maybe?
I'd be down if she went full on Yuno Gasai:
Can't be in Second place if every other place is vacant.
"[Happy End]"
Noriko is Bi though, so a harem ending isn't exactly impossible for her. She wants to make Rin cum for example, seems okay with threesome thursdays, and cares about Ami and Maya. Nakayarakawayama Harem + Rin is still what I'm rooting for.
Honestly, I feel like all the Purity Routes will have to be contrived, simply to exist. The
True End is what interests me.
Maya
isn't going to share, and I highly doubt Ayane or Makoto would if they have a choice.