^ Reeds failure to take an overt interest in her would have more to do with the difference in their ranks than a lack of interest.
True but surely you'd see the conflict in his face; you'd see the way he looked at her, spoke to her, etc and understand that he wants to but can't. You'd get the impression that his character was conflicted. But you don't see that because, as I said, I just don't think he fancies her. I don't think she fancies him either. There's no vibe either way on either part. It's just us trying to pair them off. Remember the guy she sleeps with on Risa? That's obviously her type.
Reed seems to be a bit of an immature kind of man from the perspective of personal relationships, unlike Trip who genuinely falls in love with T'Pol. I think Reed probably just lives in a fantasy world, that's why it would have been interesting to see him actually meet someone, so he could mature romantically. But he doesn't get the chance.
As for being gay, bisexual or ambigous, you can certainly read that into him. He really comes alive when he has that fight with Major Hayes. Certainly no female makes him react that passionately!
I just 'ship for Hoshi and Malcolm because the scenes we did see them in had a nice chemistry, IMO. There was a training session with hand weapons, the mess hall scene in Silent Enemy, and when Hayes prepares to lead the MACOs in rescuing her in Zero Hour, Reed wants to go along because Hoshi is his friend. Clearly, he does care about her.