Chidori all the way, she's cute, funny, and evil in a good kinda way, her personality matches Souske's perfectly, Tessa is cute also but no, won't work lol.

The woman at the end is Wraith, as previously wraith wore a suit that was that of a man and you could tell the voice was changed, the mangas tell you more about it, but that woman at the end is wraith.

A FEW SPOILERS

I thought that Chikane had a strong loving personality. Putting the type of relationship aside i thought that in a weird kind of a way her devotion to Himeko was very adorable and even when she fell to evil, but in the end i almost cried at their departure note when they had all that loving fun together and the very end when they meet up once again made me so happy, but that aside it was good.

Mitsuki was my fav character though it looks like she is the most hated, but i though her intentions were the most honest until she slept with Shinjii. She tried to help her friend fall in love but fell in love herself, and after the car accident she supported Takayuki through the roughest part and just made her real feelings show for him, and he chose to accept. I do agree though that Takayuki was a moron throughout most of the series being so devoted to his respobsibility. He just used it as an excuse to make himself feel better and hurt Mitsuki the entire time for his own selfishness, in the end his "Good intentions" and all were just his selfish feeling for redemption and throughout the entire anime i was screaming at him to say that he loved Mitsuki but it didn't happen till the very end and it pretty much just cut it shot and i was about to smash my moniter lol.