Female cats mounting? Scaredy Cat??

I'm new to the whole cat ownership thing, I love all animals and found a stray. Not knowing she was pregnant I took her in and she had kittens 3 girls and 1 boy. The boy was a runt and passed away but the rest are healthy girls which was scheduled to get fixed next month.

My first question is 1 of the babies in particular mounts the others and bites their necks. Now I've read two different things that they do that when getting ready to mate or to be the dominate cat. I took all the cats to an animal shelter I have a friend work at and she assured me they were all females so is this cat a male preparing to mate because I don't want anymore pregnant cats. Or is it really a dominate act?

Next question is one of the cats her name is Boo, I named her that because she is all black and looks like a halloween cat. Her name fits her perfectly because everything scares her. I sneezed once and she ran under my treadmill and got stuck. I had to pick it up to get her out and moving it scared her even more. My mother holds her and she'll hear the dryer go off from down the hall and dive under a chair and I can't won't come out for hours. She's never been abused because she's been with me since birth, I don't hit her or anything but I don't want her so scared like that. She sits in the window and birds fly by and she falls off the window sill. How can I help her?

Hello and welcome to TCS!

If you're positive that they are all females, then obviously you have nothing to worry about. This is a common example of dominant behavior and can occur regardless of gender.

As for Boo, different cats have different personalities. Her skittishness might be something that she'll grow out of as she gets older and more accustomed to life in your home. How old is she? Does she get along OK with the other 2 or do they intimidate her? Are you able to spend any one-on-one time with her? Over time, playing with her and petting her might be enough to help her break out of her shell. She might just need some extra TLC.

A Feliway diffuser or two around the house also might help her. It plugs into an outlet and releases synthetic pheromones that mimic the ones that cats leave when they mark objects. The pheromones cannot be detected by humans but they tend to calm many cats down. A drop or two of Rescue Remedy might help as well.

Thank you I will look into both the diffuser and rescue remedy for Boo. She is going to be 6 months Febuary 18th and she gets along well with the other kittens. Tigger (the dominate one) trys pushing her around at times but she does that to all of the kittens and sometimes trys it with the mother as well.