Awwwe, poor Mattie. Maybe she's just freaked out at the moment with all that has happened to her. Strange that she was fine at first, then decided to spaz. In your pics and videos, it didn't look like you were handling her much, but you and the vet handled her today, and you said she doesn't like to be touched. Maybe she was abused or something and is afraid of being touched? Or is having trouble adjusting to the new scents in her environment? Does she act afraid of you, or just mad? I would give her some time, a space (garage or other area?) to herself, and see how she does after a few days. If she's mean to the other cats, I don't know how that would work...I don't know but I am sorry you are stressed. Remember that what you are doing for this kitty, such an act of generosity, is to be commended. Keep us updated and hopefully Miss Matilda will chill out!