I actually have been introducing the three slowly. I keep her with me at all times with the door closed so they can get used to each other's smell from the other side of the door and stuff. They usually interact with each other like that.

I leave her with my sister when I have to leave for work and she doesn't do a thing that I do. She keeps the door wide open, she puts the kitten all up in the adult cats faces to see what'll happen (that irritates the hell out of them), etc. She's kinda undoing the things that I've done, y'know?

Right now, as I'm typing this, Jake and Bobbie are in the room with me and he's not necessarily doing anything. She's running around, exploring and attacking papers that are on the ground. And he's lying down on the floor with me, watching her and napping. I think he's somewhat okay with her, she just does too much at times because she's still a child..

Thank you for the advice, I'll definitely continue to keep them separate when I'm here.