I have feral cats as well. They don't like visitors or loud noises. When Gracie was still pretty young I found a littler of young kittens in the woods. The mom was feral so I brought the kittens inside and the mom followed me. She wouldn't come in at first but hung at the door. I finally got her inside and she finished raising the kits in my home. It took a lot of patience working with the mom but it all worked out. Anyway, the mom saw Gracie as a threat to her kittens and would chase her if she caught her near them. She chased Gracie under the recliner one time and I had to save her from certain injury! Gracie learned not to mess with Mother Cat!
Gracie had already been with a different littler of kittens when I first brought her home and she had become accustomed to bossing them around and herding them. Their mom was much more laid back. But gracie saw the kittens as play mates and she is still good friends with the ones I kept.
It sounds like your cat is trying to establish her position in the home. She wants Gizmo to know that she rules. They may eventually become friends but right now it is a battle of wills.
Do you have the kind of frame for your pee pads that locks down tightly over the pads? Our kittens did sometimes shred a pad or two but I never had one that enjoyed ripping them out of the frame. Cats are able to be trained. If you can't find any other way then get yourself a good long range squirt bottle that you can spray the cat with when she gets near the pad. You will have to keep a close watch for a few days but once she gets it a few times she will abandon the game.
There is a thread here on YT about teaching your dog not to bark. I understand that the cat is trying to torment Gizmo but he has to learn to listen to you when you say "no more!" When Gracie was young I would keep a rolled up newspaper near by at all times. With kittens around she had lots of opportunity to get excited and start barking up a storm. I would tell her "NO MORE!" and if she did not listen I would bang that paper on my hand or a near by table. It got her attention and she would stop. It may take a bit of repetition until he learns you mean business but he will learn if you are consistent.
When the cat learns that Gizmo has begun to just cool his jets around her the fun will be over and she will move on to something else. Never a dull moment!
