Based on the little pictures in the butterfly frames, I'm thinking they're (left to right): Alice, Youmu, Nue, Byakuren, Reimu, Tenshi, & Marisa. I'd guess the leftmost one is Sanae based on colours.
mr.bananas said: And Yukari, the one with the colour representing all is without colour:
Yukari "is" Gensokyo and its inhabitants make her 'Yakumo'
I see what you're saying about the "boundary" theme. But, I'm not getting the "eight-fold fence" part of it, unless you're speaking of the touhou as the "wives" of that poem.