Cats and storms and stalking

Everybody who knows me knows about my cats. Streetcar, found on Desire Street after Hurricane Katrina, Prettypurr, from a cat rescuer in the area, and Snowdrift, from a Freecycle posting.
Streetcar was here first, then Prettypurr, and they have established their relationship and it works. When Snowdrift came along almost two years ago, she upset the regime. She does not like other animals. Therefore, they do not like her. After several months of trying to get them all to fit together, I gave up. Snowdrift lives in my bedroom, she has a large size dog crate that is her ‘safe house’ to go into at night when I open the door and the other two come in.
Prettypurr and Streetcar will go to the crate when she is in it and taunt her, and I can’t get them to stop. Usually they don’t do it for long, but still, they are cat stalkers. I tell them this and they don’t care. They consider it their place, since they were here and she is the one who disrupted their happy home. They don’t care that they did the same thing, Streetcar did it to Mocha and Beauty Queen, who did not think we needed a kitten when I brought him back from Camp Katrina. He didn’t think he needed a companion when Prettypurr came along. So of course they both didn’t think we needed Snowdrift, don’t care about her story (abandoned, separated, reunited and separated again from her kittens), they only know that they didn’t like her and she doesn’t like them.
Last night – actually about 4 a.m. this morning – it started to rain and thunder and lightning. Now, I’ve had dogs who were terrified of thunder, even quiet and far away as this was, but I never noticed it in the cats before. But Snowdrift was pacing in her safe house, meowing and very upset. I got up once and talked to her and petted her and she was better for a few minutes and then started again. I got up again and this time Prettypurr ran out from underneath the bed. Streetcar had been up on the bed with me all along. He’s the one who should have issues with rain and thunderstorms, but he seems to be mostly all right, although he does get a little nervous sometimes during a storm.
So now I’m wondering, was Prettypurr under the bed to hide from the storm, or was she there to harass Snowdrift? There is cardboard around the safe house so they can’t see each other from the bed, but she knows they are there, and they know they can tease her from there.
Was Snowdrift fussing because Prettypurr was under the bed, hiding or harassing, either one? Or was she fussing because she was frightened by the storm? She no doubt was out alone in some, I don’t know how long she was on her own but I guess several weeks, I’m thinking she was probably dumped when her owners discovered she was pregnant, and when found the kittens were a few weeks old. (She was found first, the kittens about a week later, how they managed without her that long we don’t know but luckily they did.)
I’ll have to wait for the next storm to see if any of them do it again, I guess, to try to figure it out. Yeah, like you can figure out why cats do what they do.
Meanwhile, Streetcar is having his morning snuggle in the front of my bathrobe, Prettypurr is probably upstairs (where I have to clear out the cradle so she has her napping spot back) and Snowdrift is shut in the bedroom, but out of her safe house. A normal cat day in my little corner of the world.