Nice work. As you may know from my previous posts, I'm a big fan of stairs, and these are great looking stairs and a beautiful model. I'm not fond of the pose in #1, I like #2 and #3, but I totally missed the panties around the ankles in #3 until I took another look. If I could offer some advice, I would add some light to the area camera right to add some separation between the wrought iron spindles and the background, or put a light on the right side of the scene to give her more of a hairlight, and separate the spindle from the background. I might also suggest trying a few shots with her legs stretched out more to give her a longer look.
Can't wait to see more shots of these stairs in the future. Until then ... here's my contribution to the "Corset on the Stairs" theme.