If you don't get the house until January I would think about holding off telling them yet. 7 weeks is a LONG time to them!!!
I agree with this. I’d tell them after Christmas.
You need to emphasise him having them overnights means he does the parenting - washing uniform, paying for school lunches, doing their homework, feeding them etc. Basically call him out on his belief of wanting 50:50 without doing the work
And this too. Many fathers think that you will deliver the children after they’ve had dinner and done their homework, with a suitcase of clean clothes. Like you do when they stay at granny’s. And preferably just before bedtime to allow dad to go to the gym / for a drink after work.
He will have no idea what half the parenting involves, as most of it is invisible to him.
I remember a thread on here years ago, from a father who had demanded 50:50 ( and got it ) but then expected his ex to train him, which she unsurprisingly refused to do. So he decided to post on here to get other women to train him instead.
IIRC his main questions were about how to make a dentist appointment for his child and about the special toothpaste that his child needed.
Apparently he had been “ desperate “ to do things for his children for year but his wife “wouldn’t let him “.

Of course there were the usual handmaidens telling him how amazing he was and how their ex sees his child for 5 mins every decade. I particularly enjoy the posters who fall over themselves to say how easy parenting is, such as the poster who claimed that getting a hospital appointment for your child takes “ literally 5 mins”.
Yes, making a Gp appointment, taking time work, asking school for time off for child, taking your child out of school, attending GP, begging for referral, driving child back to school, getting hospital letter, arranging time off work for you and time off school for child, arranging alternative childcare after school for other child, taking child out of school, driving to hospital and waiting an hour in clinic , seeing doctor, taking child to McDonald’s as a reward for behaving, picking up bottle of wine for friend who did school pick up for you, collecting other child from friends, driving home .
Yes indeed it’s 5 mins of dad time and at least 2 x half days of mum time. Plus the McDonald, bottle of wine and favour you need to pay back.