Worried about integrating new kittens!

[Jasasope]

Hi everyone,
I have been unable to sleep due to worry over this so I'm hoping some of you may be able to offer advice please?
The story is as follows...
We had four cats, ages from 4 -15, all get along bar the occasion grumble, and we had decided that four cats was our limit and that anymore would upset the balance in the house.
Fast forward to 2 weeks ago when my Husband found a kitten in a lay by. He brought the kitten home and without hesitation we absolutely fell in love.
The kitten is in his own room, we have been scent swapping by stroking the kitten then a resident and vice versa, and there have been some interactions between him and are resident cats, some being more positive than others.
Due to not wanting to upset our residents and the new kitten we have been taking introhductions very slowly, I suppose I am worried that they will never get along so I have been putting it off.
Anyway, also being a Mum to small but very respectful children, I felt bad for the kitten being alone as I couldn't spend all my time with him in his room, and sometimes he had begun to cry when I left. This is when I brought home a second rescue kitten a couple of days ago after quite a lot of consideration, as I thought that A) it would allow the introduction process with my others to be done more slowly because my boy kitten would no longer be lonely, and B) once integrated the kittens would be playmates and not go after the older ones so much.
So, we now have the pair of kittens in a bedroom, (these kittens aren't pairing too badly, although the new girl kitten is more boisterous than I thought from when I met her at the rescue which is a worry as I already have dominant females in the house), and the our residents, who know something is afoot, in the rest of the house.
Please could anyone recommend the best way that I might try to introduce these kittens as to upset my residents as little as possible? The kittens aren't too bothered as they're only about 8-10 weeks old, but I'm so worried I'm going to end up with 6 unhappy cats and that would break my heart. I am also maybe thinking now that it was selfish of me to get another kitten for my boy kitten to play with, just so I can warrant putting off introductions.
We will continue scent swapping and I have read online about introduction tips like opening the door ajar etc to let the residents investigate, but unless the door is wide open and they can come in to the kittens' bedroom they are not bothered. The kittens have a crate and on occasion I have let a resident in to sniff about while the kittens are in their crate, but I wonder if this is fair on the kittens as it is quite an intrusion on their room, especially when sometimes they'll be cowering in there as a resident hisses at them. Any advice would be so gratefully received. As I've said, I haven't slept because of worry about this, and feel it is unfair to keep the kittens in one room for longer than necessary but I am so scared of the position I will be in if they are introduced to everyone else and they don't get along.
Just one last point on the residents, some are nervous, and one has bullying tendencies although I think this is sometimes anxiety based, my 14 year old also has health problems and so I really don't want to stress her out the poor thing. I have ordered feliway friends and am awaiting its arrival in the hope it might calm things and aid introductions.
Thanks very much

[Ruth B]

Congratulations on the two new additions, and I do think that having the two is probably a good idea, at least when they are shut in their room they can play together and having watched some kitten cams of foster kittens they really are good at entertaining themselves.

I will admit that most of the introductions I have done have been rather hit or miss affairs with very little of the pre planning scent exchanges advised. Maybe I have been lucky but they have all gone fairly well. I would advise that the soon they start integrating the better. At the moment they are very much at the kitten stage and the most older cats will treat them as children and just teach them what is and isn't acceptable behaviour. The last pair I had were 6 - 7 months old when I had them and the male one was one of those that is rather over confident and had reached the bolshy teenager stage. My resident golden oldie has quite a nasty right hook that she used on quite a few times (and 18 months on still does), but always with claws in and never causing damage.

So my advise would be, make sure you have plenty of treats to hand, and start opening the door when you are their to supervise. Let the kittens out to explore a bit and meet the resident cats. Keep the trips out short and if the kittens want to stay in the room then don't force them out let them do it at their own pace. The same with the resident cats if they want to explore the kittens room let them, but keep an eye on them. Try not to interfere too much unless it looks like someone is going to get hurt.

Don't force introductions, just let everyone do it at the pace they are comfortable with. Hopefully you will be pleasantly surprised and they will all shake down quickly.

[Jasasope]

Thanks so much Ruth B, that's really reassuring.
I will wait until the feliway has arrived and had some time to start (hopefully) working and then brave opening the door and seeing what happens. I'm terrified of things going wrong more this time than with any of the other introductions that have happened over the years, but maybe I am underestimating my older ones' tolerance. I hope I am as I just want them all to be happy!
Should I let the cats be as vocal as they like or take the kittens back to their room/ separate everyone if it gets quite noisy? Obviously I'd always step in if it looked like it was going to get physically aggressive, but I don't know how much will be too much seen as the kittens are quite relaxed so it will probably be one sided... I've been ignoring hissing etc so far, but don't know when I should be offering treats? Should they be used as a distraction if things are getting heated or to reward tolerant behaviour?
Thanks again

[Ruth B]

Introducing new cats is always a nerve wracking experience, we want the best for our cats and want them all to be a happy family, unfortunately sometimes it doesn't work out and we have to accept that the best they manage is a non aggressive truce deal.

Feliway is wonderful, but it is not a miracle solution to everything in my experience. It is certainly worth a try but but don't expect everything to be peace and tranquility just because it is plugged in.

I personally would let them be a vocal as they want to be, and even let them be a little physical as long as no one is actually getting hurt. What you will have to do is watch the cats body language as that will tell you more about what they are feeling than anything else, and will help point out when you need to step in.

As for the treats they are both a distraction and a reward. Don't use them if one is being aggressive, but use them to try and keep the tension low to start with. If one or the other is aggressive then you can't give a treat to the quiet one and not to the aggressive one as they won't understand why they don't get the treat and will see it as favouring the other. You have to make sure that you are treating them all equally, but also make it obvious that the kittens are bottom of the pecking order and get theirs last.

The hardest part I will mention, is try not to be worried yourself during the introductions. If you are stressed then your resident cats will pick up on it and are more likely to decide that the kittens are something to be concerned about. Try and stay relaxed and keep telling yourself that it will all be ok and you should be fine.