Gotta love cliffhangers... actually no... I hate them with a passion, even when the result can be predictable.
I know what you mean there! I read to be told a story not to add to it with my own crazy imagination. If I wanted my imagination involved I would just sit and dream but that's not why I read.
It's especially hard in this case since you can't really tell if Sayako is into her or not. There aren't definite tells in either direction, so you're left wondering.
It's kinda ambiguous but I think it's lightly implied that there's at least a chance. Sayako obviously at least has some interest for her and the reason she gives for it being no good if they're reborn as girl was logical enough and only seemed to have anything to do with the fact they were a guy and a girl in their previous lives.