Weird how some really small things stick in your brain - I'm now going to be always thinking of Rinko as "Apple" (please let that become Shu's cute nickname for her) because of mishearing Rinko as Ringo, lol.
Anyway, I think Narita is going to be working quite a bit on these two, they have their own issues to overcome (& I am guessing that there's some background on both of them that we haven't seen yet).
Plus the fact that they are possibly on the rebound, albeit indirectly (Shu from Aya and Rinko from Mitsuki), will complicate things. They obviously had feelings even though they were not fully realised.
However I have a gut feeling that things will work out good between them in the end (even if we end up shouting at our screens at some of the non-communication, misinterpretation, and misunderstandings).