Skirts and blouses for open house rounds should be fine. It would depend on the outfit as to whether a skirt and blouse would work for skit round. Are you able to post photos of the outfits your daughter was considering?
Skirt and blouse ensemble suggested for ice water rounds at Auburn(from the Auburn Panhellenic site):
https://fp.auburn.edu/greek/RecpicsIWT.jpg
And some skirt/blouse combos for skit round at Auburn:
https://fp.auburn.edu/greek/recpicsskitdayideas.jpg
Looking in the 2012 Greek Chic, the suggested attire at Bama for Skit Day is "a nice dress with comfortable shoes or flats." Just remember that this round of parties precedes Preference Round, and each round the outfits get dressier, so a skirt/blouse combo for Skit Round should be dressier than the 1st round outfits, but not as dressy as her Pref. outfit.