Hello all.  This adorable void is Wednesday.  I took her in on 2/17 and she was spayed on Friday 2/20.  She was a cat I found wandering around the neighborhood and I wasnt sure if she was owned or not.  No collar and real friendly. 

 I ended up spotting her sitting in the cat bed I left on the front porch and it had been raining most of the day.  I assumed she wasn't owned or she'd be escaping all the wet in her own home.  So I prepared the laundry room and brought her in. Took her to vet confirmed healthy, likely pregnant, and 1-1.5 years old.  I reached out to the former foster momma of one of my resident cats, Goose, and she recommended a spay place that would do a spay/abort that she uses for her TNRs that does spay events.  They took care of her and I brought her home.  

I moved her to one of the bedrooms and I've been alternating between keeping her in the bedroom / my 2 cats (a 4 year old orange boy Goose, and 16 year old grey Noro girl) in the house then switching off.  She's been pretty good but still getting adjusted of course.  She will be fine and very lovey and chill and then she gets hissy kinda randomly.  Some of it is me moving around the house (not always but sometimes).  Sometimes I'll be petting her and she gets hissy and may attack my hand a bit.  (Not excessively just scratches though.)  I'm monitoring for the poofy tail or saucer eyes or anything to see if she's overstimulated.   She is growling/hissing at my cats if she sees them through a door or whatnot.  And one Saturday I switched them out and didnt know Goose had snuck out and they had a bit of a standoff.  Not excessive fighting but I separated them with a pillow /my office chair and guided her back to her room with a pillow after Goose hid somewhere in the house.  

I guess I wanted advice for how to proceed.  I am doing the eating both sides of the door.  It's just hard because I can maybe open the door a Crack but I don't have a way for them to see each other but not have access to touch each other.  I tried baby gates and this screen door attachment for my bedroom but it's not working.  (My cats can circumvent this they are only smart when it's inconvenient.  Lol)  anything you suggest?  Any ideas for getting her to calm down or figure out how to reduce hissing and the aggression?  I'm trying to redirect her to toys when she's hissing but she's not always interested.   (I use a grabber so she doesn't learn to go after my hand or anything. )  any and all suggestions welcome!

Looking for advice reducing hissing and intro to 2 resident cats