Collars are do-able. It does take fiddling. The .obj loads in the cloth room with the collar standing straight up. So you have to fiddle with constrained bits until you get a render that falls the way you want and save that prop out again. Vertical Pleats? I think it could be done with a whole boatload of point editing, but I would not want to try it.

Oh, something I learned the hard way. If you make a lot of tiny cuts (spaghetti straps, say) it is better to cut the material group in VF, but don't delete it. Use a transparency map on the material group in Poser.  The render time goes way down. Poser chokes if there are too many missing polys.