Help needed introducing my cat to my kitten

Hi,
I am in need of some help introducing my kitten to my cat as this is my first time doing it, and have a bit of a tricky situation. Both cats are utd on vaccinations, vet checked, etc.

About the cats:
-Cosmo is a 5 year old neutered male, I've had him 4 years. He was a formerly feral cat that I adopted. This is the only home he's ever had. Before I adopted him he lived at the vet clinic I worked at. He is very attached to me, loves other animals, but is also a timid/shy kitty with some anxiety issues (self-harm, fur pulling) when he's alone. But he's a very good, well behaved kitty. The day before kitten came home he started having health issues (not contagious. It was vomiting caused by constipation) which the vet gave him meds for, and as of yesterday is doing much better. He is not at all food motivated. Instead, he is motivated by play and attention. Because I work in a vet clinic he is very used to smelling other animals on my clothing. He was around other cats for the first year of his life, and still interacts with other pets in the home. He has always reacted positively to them. In fact, he seems to love other animals more than humans.
-Noah is a 4 and a half month old neutered male. I adopted him 8 days ago. He is currently staying in the spare bedroom downstairs which has been turned into a kitty haven. He is an active kitten, likes to play, but is also snuggly, very laid back, and confident. Very food motivated and adapts very quickly to new situations. The rescue I got him from said that he likes other cats and when hissed at by the foster family's cats he ignored them and was fine with them.

The tricky part of this is that Cosmo the resident cat stays in one room (my bedroom) and has never left by his choice. He did this when he lived at the vet clinic as well. The times I bring him out of the room his heart rate goes way up, he cries, etc. He adapts fine to changes within the room and I have turned it into a kitty playground- cat towers, shelves, toys, etc. He seems content there and is only territorial about his cat tower when he's sitting at the top level of it (I have a second cat tower for kitten). And even then he'snever aggressive, has never ever hissed, etc.

I am currently following the Jackson Galaxy steps to introducing cats, but have done tons of reading from other sources. My plan was scent swapping, then have one on each side of a closed door, then gradually open the door bit by bit, then bring kitten in a carrier into Cosmo's room- all over a period of a week or a few weeks depending on how they did. I started by scent swapping. I switched their toys back and forth, I rubbed both cats' cheeks and chin with a washcloth, switched blankets around, switched scratching posts, and brushed both cats with the same brushes. I have also taken little bits of fur and put them in places Cosmo likes best. I started doing this on day 2 of kitten coming home. Noah kitten is super chill and is indifferent towards resident cat Cosmo's scent. When I bring scent swapped objects in to Cosmo he immediately investigates them, smells them for a few minutes, then goes on with his usual behaviors and activities. Sometimes he will go back to the scent swapped objects randomly and give them a little sniff. He rubbed his cheeks on the brushes with his and Noah's fur on it, which he did even before we brought kitten home (he liked to brush himself). After sniffing he didn't mind me petting him on the cheeks and chin with the same washcloth I used for scent swapping to bring back to Noah.

Last night, with the help of my mom, we put Noah in his carrier, brought him upstairs and set his carrier outside of the door of Cosmo's room (door closed). My mom fed him wet food and I went in with Cosmo and gave him catnip, petting, and played. It's recommended to feed both cats at the same time on either side of the door, but Cosmo is a very finicky eater and does not get interested or excited by food. At first, Cosmo hid under the bed (possibly because of the commotion outside the door), then did totally fine. I did this for about 10 minutes and ensured that they wouldn't see each other at any point. I spent extra time with him afterwards and he was totally fine. Noah did fine as well. I planned to do this a few more times.

Here's where my questions come in. The recommended next step is letting the cats swap spaces to mix their scents in the resident cat's territory. Should I still do this if Cosmo gets super worked up about leaving his room? It would be a very negative experience for him to be put in a carrier and forced into a strange room, which I am afraid he will associate with the kitten's presence and make him dislike him. Will it be okay to skip this step of room swapping?

Is 10 minutes each day of them on either side of the same door enough time? At what point do I know when to move on to the next step and let them see each other through the door opened just a bit?

What is considered a good reaction to scent swapping? Are Cosmo's long sniffing sessions okay or should I keep doing it until he's completely indifferent to the scent swapped items?

I have a feliway diffuser plugged in (because of Cosmo's past seperation anxiety issues). I have seen that Feliway now has a special multicat diffuser. Is it worth it to purchase the seperate multicat diffuser, or will the regular one still help?

If you have any other tips, hints, or suggestions to make this process more smooth and positive I would like to hear them! Everybody I know has been saying I'm being way too cautious and making this more complicated then it needs to be, but I just want to make sure I set them up for success!
Thanks in advance!

Hi, and welcome to TCS

It sounds like you're doing all the right things to me. I wouldn't make a big deal over space swapping - if anything, it sounds as though it will create a negative association on Cosmo's part.

With the scent swapping - I'd say that extended interest is just fine. It's negative reactions that you need to be cautious of. So long as body language is good and there's no hissing/growling etc things are going well.

I've never come across the special multicat diffuser. The key with Feliway is to ensure the whole house is covered. The pack should state the area that one diffuser 'treats'. Ideally, you want to have diffusers at strategic intervals around the house so that everywhere is covered by the Feliway.

Be prepared to take a longer timescale than a week or so. I think the problems will come in this case if you try and force the final stages of the introduction.

Carry on with the joint feedings - and do please offer Cosmo food at these times too. It doesn't have to be a meal - his favourite, yummiest, stinkiest treat would be just fine. Eating in each other's presence is a really strong indicator of how comfortable they are with each other. Toys could potentially backfire, as could catnip. If you need to use a non edible reward stick to cuddles and petting.

I really don't advise putting Noah into Cosmo's room yourself. Cosmo seems to have major territorial insecurities still, and forcing the issue that way could go badly wrong.

Instead, allow Noah full access to the rest of the house once he seems ready for it, and set up a screen door or stacked baby gate at Cosmo's room - just to avoid unsupervised access. When the time seems right, just open up access to Cosmo's room - initially only under supervision. Then let the cats make the decision. Over time, you'll be able to have Cosmo's door permanently open.

Hope that all makes sense.
These articles may help too :- [article="32680"][/article][article="29726"][/article][article="32735"][/article]

Thank you for the advice and links! I'll try giving Cosmo some food tonight during the joint feeding. He's currently eating urinary SO (free fed), so treats have to be very limited. There are a few dry crunchy treats he's allowed to have on rare special occasions, so maybe that might be an option in addition to food during those times.
How will I know when Cosmo is ready to have the screen/baby gates up while Noah roams upstairs? I'm willing to give them however much time they need.
When the baby gates/screen door is up should I start with the door cracked or all the way open?

I guess altogether I'm pretty nervous that it won't work out between the two of them. Cosmo and Noah are the first cats I've ever owned, so this is all very new to me.

As Noah is so chilled, I think he's probably ready to have freer access to the rest of the house. I'd suggest you put some of the scratchers he's been using around the house first. This will help spread his scent around the place and (hopefully) prevent, or at least reduce, scratching damage being done to your furniture If you don't have many scratching posts/trees, cardboard scratchers are a great alternative for this purpose. They're cheap, most cats love them, and they don't take up too much space. It wouldn't be a bad idea to introduce a cardboard scratcher Noah's been working on to Cosmo's room. It may give a stronger indication of how he's feeling about the introduction process so far.

With treats, a little plain cooked meat can be a great option. One of my cats is on the S/O kibble too (in combination with regular wet food in his case). I can't imagine that a little meat will cause any problems.

You could introduce the baby gates or screen door now, just to give Cosmo time to adjust to the change. I'd leave it at least another couple of weeks before leaving the door even partly open when you're not around though. It's important that you're there to supervise in the early stages, and with each change.

I had a similar situation to you when I introduced my current two, and the introduction process was a little unorthodox to say the least In my case, it was the newbie who was very nervous and the resident who was chilled. I ended up having to just trust my instincts, as the house layout and resident's habits made conventional procedures almost impossible. You might find my thread interesting/useful: [thread="294645"]​[/thread]