Another rush fashion question!

[husky_03]

a couple more questions:
1. on the days when we're given a tshirt to wear, would it be okay if i wore a cardigan and/or necklace with the shirt? or would it be seen as disrespectful since it's not uniform with all the other girls?
2. would it be okay if i wore a skirt and blouse for pref night? the outfit is mostly black and is still really formal.

thanks for all the advice!