Really glad your dc are home Name. I doubt he'll ever bring them back on time, that means having to do as he's been asked. Maybe for your sanity you could ask him to bring them home half an hour earlier next time, but add on an hour in your head. That'll probably be nearer the time he'll get back !
As for not buying your dc a xmas present this year, how can a father do that? I certainly wouldn't be buying your ex SIL's dc any presents from now on. His sister, his family, he can do it, especially as she sounds horrible. I also wouldn't be nice about her to your dc. I'm afraid this is how I am with my ex-SIL - she's a whole thread on her own.
Lilac sorry to see your WN is being his usual charming self. D'you think he's going through the honeymoon period with his new gf, and playing happy families in his head? Perhaps he has visions of them as a little family toasting marshmallows over an open fire !
I'm guessing you wouldn't mind some o/n stays, but the fact he's doing all this after the holiday announcement is just pathetic. Seems likely it's just to unsettle you.
Nats Hope GMB don't find out about your "criminal record", they might not let you on the sofa !