You need movement handles for the the lower skirt.
Is that chapter two in the manual Chapter 2: Adding Optional JCMs to a Dress?
No, the movement handles were added automatically, you just also have to use them manually. This is normal and expected. You select the UpperHandle or LowerHandle in the Scene Tab to move it. Having the skirt move automatically with the legs is a poor choice for versatility of an item and takes a lot of functionality out of the user’s hands (yes, there are differing opinions on that, but I always err on the side of user control).
The Optional JCMs are for when you bend the skirt a lot, say for sitting, and it looks very distorted and not like a normal dress would move. JCMs help to smooth that out.
Autofit is used to fit Gen 4 clothes to Genesis. It is a faster but not as effective method compared to converting through Transfer Utility (as in the manual). Autofit also does not add the smoothing and collision modifiers.
I still think it’s awesome that you’re rigging a house dress, by the way.
Also: Fisty and islandgurl, welcome to the party! 4.5 Pro is superior to 4.0 in a number of ways, not the least being the big improvements in the way smoothing and collision work (making meshes with more small details much more possible). After the one long evening I spent running the dup ids script over all the older stuff in my library, I’ve never looked back.