You're totally right Andrea! Is the same gown.
I was thinking that the black one (below the jewels) its perhaps this
About the wedding gown, after searching on my Sissi CD the one that looked more similar was this (although the sleeves aren't the same)
I wonder why Hungarian traditional dress always has that little apron at the front...
The majority of traditional hungarian gowns have an apron, not all. I don't think that it has a special meaning but being only their style.
I wonder what the white one with embroidery next to the uniform (Franz Josef's?) is based on...never seen a picture of that.
I think that it must be Franz Joseph's. I have never seen any hussar uniform of Franz Joseph (neither the one used in the Coronation), so I think that it must be his (I doubt that it belonged to other man... Who??
)