A. My guess is that it will be an emotional day for your daughter without her mother at her wedding and since your wife was asked not to wear the same color as the bridesmaids and mother of the groom, she should respectfully select a dress in a low key, yet elegant, color. This rules out any "look at me" colors like red, cobalt blue, fuchsia, bright yellow, etc. White and ivory are of course off limits, and it's best to avoid black as some people view this as the color of mourning. Likewise, the style of the dress should be somewhat reserved, no short hemlines or plunging necklines.
Here are some suggestions in appropriate colors: