For my wedding I let them pick both but I did list 5 colors
When I was a BM for my SIL's wedding she chose dress and shoes, but the shoes did not and would not fit me. She really did not have a choice, but let me find a pair that would fit. I was a 9.5 double wide at the time.
When I was MOH the first time I wore what she wanted down to the shoes (divorced year later)
The second time I was MOH for her I picked Dress and Shoes she is still married. I kind of expected this and I really wish she had not divorced him.
Vow Renewal - I am not having attendants, so people will wear what they want. My sister is the officiant and she is also going to wear what she wants.
For my sisters wedding I will be her photographer and she said I could wear what ever I wanted from one of the BM's gowns to a Suit. I am going with a Tunic and pant in her colors. So that I can feel dressy and yet not worry about a dress for
those low angle shots. I hope to be a size 12/14 by then!