easily dropped?

Tbh every house has their fair share of not so attractive girls. Unfortunately looks do hold some importance during rush, but honestly, if you're an incredibly well rounded PNM, any house will want you. If you make up for your lack of attractiveness with grades and involvement then houses will obviously note that. If you're incredibly involved then you'll have a pretty good shot at the majority of the houses here.

You should do just fine.
not every girl is drop dead gorgeous, makeup goes a long way many many times

Personality/manners/mannerisms/looks play the most part. I know plenty of people with high gpas that don't end up doing jack with their lives and vise versa

Your OOS status won't get you in easy-peasy. Usually someone in each sorority who knows someone else will contact a third person who will be double-and triple-checking your stated resume of insanely high test scores/gpa, presidency of many clubs, volunteer work and tons of extracurriculars. So please be sure your resume is correct in its details. As to your stated average appearance you will be treated warmly, kindly, and politely during recruitment as this is The South and we have our manners and reputation to uphold. One of us will be giving our name to you, and we respect and uphold that name in the grand hope you will do the same for life should you accept our bid. Now you go into recruitment with your smile on and your head held high and wow 'em!