baby gates do not stop most cats. (99%).

I would definitely confine the cat at first, and then continue to do so whenever you are not home or cannot supervise (like when you are asleep) until you are POSITIVE that 1) Ebony feels comfortable and 2) you can REALLY trust both pets together. Confrontations can happen fast. I would chose which ever room you you wish her to retreat to if she feels threatened. I have found, that whichever room I chose to start a new cat in, the new cat will always go back to that most familiar place if it needs time alone. So if, for example, the spare room will have its door closed to her at a later date, then chose the living room (they can get scared if they cannot get back to that familiar spot.). Realize that some cats will acclimate faster than others. I've been through everything from 1 day to several months until the new cat felt completely comfortable.

Hope this helps more than it scares you LOL