I decided to flat-line the skirt after, it's just so much easier to deal with that way! So I found a cotton/poly voile in the stash (so happy to use this up!), cut it out and used temporary basting spray to baste the lining to the demon fabric.
I stitched all the seams, pinned the skirt onto the foundation bodice and it is too small in the waist. Ahh! I had the same issue with the bodice and think I have finally figured out what the problem is. My demon fabric doesn't stretch like the cotton muslin I used for the mock-ups. Actually I don't think it has any give in it at all. So what fit beautifully in the mock-up isn't working in the demon fabric. Awesome huh? :P
The only thing I can do at this point is sew the seams with the smallest seam allowance possible (like I did on the bodice) and hope it's enough. If not I'll have to add a panel or something, which even though it won't really show with the other layers of fabric I have planned I'd be bummed to do. I'll know it's there you see.