Help!!! Cats going nuts!

I have a kitten- she is really good forthe most part- but she is an alpha female & does not get along with the other cats when I take her to visit my Dad. I raised those cats- which are female as well which are sisters at my Dad's.

Then I have another issue. My neighbor has a 10yr old spayed male which I watch every Monday because she works late hours. He used to love me.
Now she just got a new boyfriend & he hates the world- he even bit me.
He hisses at his mama (my neighbor) can't stand my kitten. And growled & hissed the whole time he was here.

My guess is that he senses that he is no longer the only male in my neighbor's life anymore & is acting out.

Now my kitten is going to be spayed in January- I hope this will subdue her agressiveness. I really don't know what to do with her & other cats- she is great with people just not cats...
She is a Russian Blue/calico mix.


Would appreciate any help...Thanks!!!!

I would say that spaying her should calm her down! (mine always get fat and lazy after that Until then maybe you could just kinda keep her away from the other cats????

I think that just because you raised the other cats it does not necessarily mean that your new kitty will accept them also.
New place and strange cats mean new and strange smells. Cats (fixed or not) react differently to these smells. Some cats get aggressive, some shy away from them, some are curious about them. It just takes time for them to get used to the change.