If they are not all out brawling, they should be fine in the future, but did you isolate Sasha before introducing her to the resident cats? How you introduce them will set the tone for the future.
Yep I put her in a seperate room then put her in the carrier and let the cats and dog sniff her. I later took her out and that's when there was hissing and swiping so I isolated Sasha again. Then I let them hang out on the condo and that's when her and Sophie started to bond. Anna still hisses her lots. She's being isolated over night though.
I was my3kitties when I first joined CF. When we added Smokey, I think I asked catman (the admin at the time), if I could change my name to my4kitties. I'm not sure how you'd go about changing your name now. My guess would be to PM a mod?