I know this poll is very old, and I already saw your drawing of Reimu, but I'll still suggest Suika in your art style! Though she's not in here, or maybe Sakuya then Marisa. For couples, I like Reimu x Marisa (Touhou OTP <3) and Satori x Koishi.
Satori? I don't even know which that is! I thought Remilia would do way better, though. At least above Sakuya. I'm not big on her, but most people seem to be in a pervy way. Of course, Cirno's the strongest and Flan's the cutest.