IMO, your lighting only worked on #3. That's the only photo where both the whole model and the bike are well-lit. It would have been a much better shot with a second light or reflector at some degree to camera right. You could take some time to darken in the background - this way the shadow and the texture of the background won't really be visible. I think that would make it look better.
Also watch the wide angles.. the 12mm is too wide for shots where you don't want distortion... and usually distortion is unflattering to models (unless you want to make their legs appear to be a little longer). If you were limited on space, I guess that's a valid reason for the wide angle.. I'd want to use a 35mm prime at least for something like this, maybe even a 50mm. Of course then you'd have to be able to back up quite a bit.