Well, you knew I was going to answer...
From my observation of Gamma Sig being on campuses in which APO is already there (and very co-ed), USUALLY Gamma Sig isn't affected. People will choose which organization that want to join. Either GSS will be their best fit or APO might be. Plenty of Gamma Sig chapters do very well with APO there.
To answer your other question, I personally do not have a problem with a soror also being a member of Alpha Phi Omega as well. I think eventually you'll have to make a decision about which organization will get more of your time. I say this because I know of several sorors that were actually APO members first, then pledged GSS and eventually just gave their time entirely to GSS. They didn't necessarily give up their APO membership, they would still attend events and such, but we knew them more as GSS sorors.
If you'd like we can chat more privately about it. There's more to say.
