As for my predictions who the choosen girl will be, well i am not sure yet but i have already an idea who it isn't going to be.
The anime has skipped on Isara's initial story so much (that she and her familiy are really poor , the part that she got bullied, the scene that Yuuki found out that she was working part-time at a fastfood restaurant eventhough it's not allowed etc), i don't think the anime will go for her (very unfortunate, seeing that she was one of my favorite characters). Also they skipped another thing, but i will save that for the Satsuki part
As for Michiru. The anime has skipped out on the entire part (including the welcomes party)that she was initially not a member of the club . In episode 1 she was already a member in the anime version.The anime did save lot of time by doing so though. While that minor change doesn't mean much, i don't think the anime will go for her seeing that she doesn't look like a main heroine material to me (sorry Michiru )
Mifuyu hasn't done much in the anime , but that was also the case in the beginning of the game. So i have no comment about her.
Satsuki has more appeared slightly so far than expected. Also instead of Isara comforting Yuuki after he was "forced" to be the canditate it was Satsuki in episode 2 who motivated him. Plus in episode 3, the anime already showed how bad relation between Satsuki and her older sister Hazuki is.
Eventhough the people in the anime forums are saying that the anime seems to be leaning towards Chisato, i am not entirely convinced yet.
All of the socalled hints ( the flashback scene when Yuuki and her being children, chocolate scene at the end of episode 2, her osananajimi antics and probably more that i cant think of now) were already present at the beginning of the game. I know that she is probably considered to the main heroine and that you had to play her route first, but everything so far is still the same as in the game.
So my likely guess will be either Satsuki or Chisato (which isn't a suprise). Unless the anime wants to go for a heavily dramatic route with Mifuyu
I am already writing off Isara and Michiru.