It seems that Kyoani is trying to give Isshiki his own romance sidestory. At this point (ep7) he is clearly infatuated with Kumin.
From episode6 it appears that Kumin likes Isshiki, though she is probably too much of an airhead to even think about romance. I wonder if they'll ever make any progress or if Isshiki is going to be NTR'ed by Kumin's pillow forever.
At the same time episode7 put a lid over whatever hint of romance between Yuuta and Shinka existed before. From the time she revealed her true self, Yuuta doesn't seem to care anymore about her. On the other side Shinka is aware that there's something going on between him and Rikka, and she approves that. There's absolutely no hint of jealousy at all.
By contrast she doesn't seem to approve a possible relationship between Isshiki and Kumin, but personally I think it's more because she thinks Isshiki is just a hungry wolf looking for a prey, and she doesn't want Kumin to be taken by such a jerk.
I don't really see jealousy, but who knows, maybe I'm wrong.
Meanwhile Shinka and Sanae keep getting closer to each other. The way Shinka is forced to take care of Sanae in spite of their continous bickering kinda reminds me Himawari and Sakurako from Yuruyuri, but maybe it's just me. I don't think Kyoani will go that far, but they're bound to become
heterosexual life partners at the very least.
After all, when you consider RikkaxYuuta and KuminxIsshiki, what remains is SanaexShinka.