I've a problem with the dress called 'Crimson Rose'. You can still see a part of the character's leg.
I don't think that is a bug.
I know, the right side is supposed to be seen, but are you sure the left one too? I've marked the spots on the picture:
Now I don't know either.
Try Thiccfying Lust, I never really let Lust wear any of these dresses for more than a few Minutes.
That dress has splits on both sides. If it was hanging straight down, you would see both legs.
As mentioned, the idea is that there's 2 slits. I could see about making it 1 slit though.