General recruitment questions from a PNM

[SouthernPNM123]

I'll be rushing at a Big XII school in August, and I have a few general questions.

Does a recommendation letter hold more weight if it's from an alumna of my school's chapter?

Does having more than one recommendation letter help at all?

And finally, the dress I currently have picked out for pref is fairly conservative everywhere except the back. It's black, has a high neck and long sleeves, is somewhat loose fitting, and comes more than halfway down my thigh. The back, however goes about halfway down my back and has cut outs. Is this appropriate if done with tasteful hair and makeup, a clutch, and a simple heel?

Any help would be much appreciated!