God-damnit, I ship them all! Kou and Rin, Aoba and Hifumi, Nene and Umiko, Hazime and Yun, I ship all of them!
I also thought about what these couples would be like on their first 'night' together, and I came to the conclusion that they would all be nervous and awkward aside from Umiko, who would be assertive and dominant, yet also like a child in some respects.