Things got.... interesting!
The scent exchange was funny... Well... Gracie could care less - attacked her food as though she hadn't eaten in a week

didn't even notice anything different. I got three different wash cloths and rubbed one on each of the kitties, Lucky, Bugsy and Hope. Then I put them under Gracie's plate. Not a reaction - none.
While she was eating I rubbed other 3 wash cloths all over her - one for lucky's plate, one for hope's and one for Bugsy.
Lucky didn't care, Bugsy ate and found the wash cloth quite handy to cover his plate

and then there was Hope... ah Hope had a hard time....
Hope smelled every inch of that cloth very carefully, as though it would jump to bite her and after a long while doing so, walked away refusing to eat the food.
Only after taking the cloth out she ate... I then folded the cloth under the plate, and she ate the rest...
Hope seems to be the one stressing out the most about this situation - I need to be very careful with her...

Lucky has been extremely curious with who is behind the door - anytime I am in the bathroom she is right there, scratching the door... If I open the door, she watches Gracie very carefully

Today I opened the door for them to see each other - the scene was priceless: Standing outside of the bathroom the three resident kitties, very quiet, capable of hearing a pin drop quiet; inside Gracie, quiet, with the occasional Hissssssss, hissssssss, hisssssss.
She doesn't have a problem with Lucky; whenever Lucky watches her, she just goes on to grooming herself, eating, or whatever... But the others do make her nervous.
How long can she be inside of the bathroom?
I work out of my home, and visit her all the time... Sometimes I just bring my laptop and stay here with her...
She is not stressed, and doesn't looked depressed at all... She is eating really, and I mean REALLY well...
What do you think? I do not want to ruin this, and want to do the absolute best for this to work...