The hip and crotch problem is due to the stitching of the thick material on the suit. The stitch makes it bulk up in those areas, particularly the hips.
There is one in the commerce section (not mine):
https://www.sideshowcollectors.com/forums/for-sale-trade-action-figures/183347-hot-toys-nightmare-batman.html
Imo, you should sell the pieces separately, you will get the most money out of it. Last year I parted this same figure and kept the head for the AOU Cap and made most, if not all, my money back.