Hi there!
It's probably best to wait till the madness of Christmas is over to bring a new puss home now - but there's nothing to stop you getting the process started now, have you been in touch with your local rescues?
I'd tend towards youngish cat rather than a baby kitten as you've got quite a big and lively brood - a sort of 'teenager stage' cat would probably cope with all that better than a little'un.
How old are your kids?
Yours sounds like a fun house!