Well this is a tough one to answer. As I'm typing this 3 of my cats(Storm,Sky,and Ziggy) are fighting and chasing each other. Paizly was still a little kitten when she was introduced to Taz so all she wanted to do was to play with him. She was older when you had G staying with you but it seems like he didn't like other cats so maybe she also sensed this and this is why she hated him. I've always found it easier to introduce a younger new cat to my already owned cats because they don't seem to cause as much of a threat to them. Yes, there will still be hissing and growling but I've been lucky and it's never taken more than 1 week to stop.

The main problem with getting another kitten is that you really don't know what their true personality will be like. You'd hate to get an alpha cat. I'd also recommend that if you get another cat that it be a male. If I had 2 females like my Pearl, there would be a lot of fighting and most likely pee wars around here. I'm very lucky that Ziggy and Pearl are total opposites. Getting another cat/kitten would provide Paizly with a good play buddy and companion though. If you think she'd like another kitty then I say go for it but if you think she should be an only kitty then do what's best for her. Cats usually never get along all of the time just like kids. Good luck.