We have several from the FFVII-verse, but in our case AC did happen. It's funny watching your canon and saying to yourself - "Wait, it didn't happen exactly like that...it was more like this." There are points where canon viers into strange and interesting territory.
Some of us have been here over a year, but myself, I have been "here" for about 10 months, I believe.
As to who is in residence, we have - Tseng, Kadaj, Yazuu, Reno, Nero, myself (I tend to go by Geny for the planetary being reason below), and Zack, who comes and goes from time to time. He isn't really solid and tends to disappear into lifestream and act as sort of a "helper" to Aerith who resides there. We also have planetary beings - Omega and Genesis. Nero also acts as a being of some planetary significance.