Sleeping in the same room is actually motivating Louisette to go to bed more easily at night. TJ doesn’t always sleep through, but having Louisette there or not doesn’t seem to be a factor.
I’m sure that at some point they’ll be joining forces to stay awake, and that Louisette will soon realise how potent her power to wake TJ is. We do have a spare bed in the girls’ room for use when we need it.
So, hopefully all will stay in pretty much this arrangement until Louisette is old enough to need her own room (possibly 10 or so; we’ll see).