I like your space plan and where you're starting. Detachment is its own roller coaster I'm finding. One minute I'm a professional and think I could write a how-to book on it and the next day I'm woefully inadequate at it and I'm searching all over the place for a how-to book on it. LOL
The kid communication thing... hmmm...
On days that D is with me, H calls only before her bedtime... so around 7:00-7:30 pm he'll text saying "is it a good time to call?" or whatever. I'll either say, "Sure!" or "she's in the middle of dinner" or "she's in the shower she'll call you once she's out" or something like that. It's EVERY SINGLE NIGHT she's with me. They talk for about 5-10 minutes about her day, karate, the dog, friends, a good book she's reading.
When she's at H's apartment I do the same. EVERY SINGLE NIGHT. It's not a "do you want to talk to mom" question. It's "Dad wants to talk to you" or "Mom wants to see how your karate class went". Done.
If H and D were in the middle of playing the Wii and I texted and said, "does she want to talk to me?" she'd probably say no but that's not the option I'm giving her. *I* want to talk to her so *I* will.
You can't control how your H pursues a relationship with his kids. You can, however, teach your children that it's basic respect to speak to their father at least 2 minutes each day that he calls. It doesn't sound like HE wants to have that kind of parental relationship though so your hands are tied in one aspect.
Does he ask if they want to talk every day?
If he's open, and only if he's open, I'd suggest for the kids sake that IF he's going to call to speak to them that he do it at the same time every time so the kids can look forward to it (or dread it, either way) and that shows THEM that HE'S interested in their lives (which is all kids want anyway).
