Well, obviously the color illustration with Miku and Shidou was before Shido became Shiori.
And well, from what I can see Miku is trying to go all dominant on Shiori while Tohka is jus confused in this mess
.
Dat Miku's illustration, I didn't notice but she probably has the biggest rack among spirits... oh wait... =_=; forget that.
Oh, and Mana looks very broken I recommend to not start to take a liking to Miku because she may end pretty dead.