Can you do more of the above...Where you place Audrey into Elliot's room, and leave her in there for a bit of time...not long...say 20-30 minutes.I caught her venturing into his room one time but she scurried away when she saw me coming.
By doing these type of 'Room Swaps'...and more "Scent Swaps"....you are allowing both Audrey and Elliot to smell and leave their own Scents in each other's rooms.
Exchanging Scents and Mingling Scents will lessen the 'unknown factor' ...for both cats...and lessen their fears.
If you can get more interactions,...like the one above...then that is fantastic....I opened the door for her and just held him on my lap, and she came a few steps into the room and watched him for a couple of minutes. No hisses or growls. They were about 7ft apart. He was watching her too. The she turned around and wandered away. I gave her a few treats afterwards. That was a good moment I think.
" Of course, she's a cat, she will just be able to tell that I want her to do it, and saunter off..."Thinking about how to let them encounter one another in a more controlled way (!) when the time comes, I think it would be ideal if she would scratch at the door again and I would just let her in. But there's no guarantee she will do that! - Of course, she's a cat, she will just be able to tell that I want her to do it, and saunter off...
Goodness, this line above is hilarious!...Yup, she will know what you want her to do...and do the opposite...because..."she's a cat"
It's really hard to say what is best to do for the first 'controlled encounter'.....Is it better for me to hold him at a safe distance at first, and then set him down when she's had a couple of minutes to observe? I feel like he is just going to be super excited and rush towards her! I could try distracting him with toys (he really likes ribbons - so does she) but she is just going to seem like the best toy in the room...
I think what you are doing is excellent. Your instincts are really good.
Does Audrey still growl at you...if you have the Scent of Elliot on your hands or clothes?
I would probably just keep him on my lap, and do more of the observing...that you are already doing.
A ArtNJ ...has given some great advice...so I'd be curious to hear...how he would do the 'first controlled encounter'.