Hootie, the individual in question was 2 years behind me, so she's graduated by now. Unfortunately I now live too far away from my chapter to really help out with anything.
I have a thought on the dress thing - I once saw a choir perform, where all the men did the standard "concert wear" tux, but instead of standard black and white, the women all wore different brightly colored dresses - like jewel tones. If you did something like that, you wouldn't have to worry about matching colors. You would just specify sleeve and hem length, and things like "no backless dresses", and let everyone pick out her own. That way, everyone gets something she likes, and you really stand out during pref.