I know very little about style and beauty other than long evening dresses are a big no. You'd probably be mistaken for one of the bridesmaids, and the bride might get a bit
about it. Assuming she is a bridezilla type that is. Even is she's not she'd think you were being a bit upstagey.
I got married in a castle, and even in the middle of summer the guests all wore knee length dresses with coats or jackets and I froze half to death wearing an evening dress more along the lines of your choices above.
I also went to a winter wedding in a castle, and again it was knee length with coats and tights.