Just tested the new collection hide helmet function with a disguise and it no longer hides the disguise helmet like the existing Settings >> Gameplay >> Hide helmet function does.
Outfits is a huge step forward but this part makes me sad.
No more being a non vampire for a while to see my old face any more...
No more northwind disguise with the cool looking dirt without the stupid hat.
No more courier disguise blend in with the natives without the stupid hat.
ZOS gives and ZOS takes away.