(Just as an aside, it helps us to reference them if you number the images. Thanks for only putting up a few for critique, though.)
1) Sorry, IMO not a keeper. I'm not a fan of the B&W conversion on this one, partly because there's still too much detail in the upper left corner (certainly the two bright rectangles should be cropped or cloned out). This crop makes her body parts look completely separate: I see a head, with an unfortunate crop diagonally across her throat, one hand cut off at the wrist and knuckles, and a second wrist. In general you want to avoid cropping so close to joints, it makes the subject look amputated. I'm assuming she has her left elbow up on something, is tilting her head to that shoulder, and brought her right hand up to her left arm. If that right hand had been moved to camera left a bit, so that the fingers were complete and were brushing against her cheek (maintaining a continuity), this image would have been better.
2) Better, though it seems a bit underexposed to me (at least on this monitor). Nice masculine pose for the subject. There's too much going on here, though. That shirt is way too busy, especially since a good chunk of it is white (brightest parts of the picture, drawing the eye). The background is interesting, but there's possibly too much texture in it for a portrait (certainly too much in conjunction with the shirt). I think this would benefit from cropping some off the top.
3) Far and away my favorite of the bunch. I like that you got down to (actually, below) her level. I like the square crop, and that you almost filled the frame with her (but left enough to get that nice background in). I might suggest leaving a touch more at the bottom of the frame - I don't mind the crop across her foot, but you're close enough to her other knee that we're starting to get the amputated feeling I mentioned above. It's not that bad, but it is an inkling. What B&W conversion did you use? I only ask because her skin seems flatter and darker than I would have expected looking at the wood behind her.