After going through the first batch of social events, I frankly have to say that, were I in Rean's place, I'd pursue Emma over Alisia/Laura any day of the week. But it really looks like the game wants me to end with Alisia <.<
As for Fie, I still haven't reached the part where the truth about her is revealed, but if I had to guess, I'd say she's that black cat that was observing Rean at the end of the first abandoned dorm exploration. They are making it, like, painfully obvious.
