Moyo?
I can see Rika happening in a few updates, tbh. I mean, her whole friend group just had friend group sex without her. Plus that'd probably cause drama for Rin since she's told Sensei not to bang her mom, and Rika should know it'd mess with Rin.
Once again, I say Poor Rin:
The True End is set after the Purity Routes, so they seem to be intended to be comparable to filler or fanservice. Albeit, I wouldn't blame people if they just pretend any kind of happy end they get, is the actual end even if it's not.