Great news re: good nights
I think if you push that first A time, he will naturally sleep a little later in the morning, though with an 11hr night, its not really an EW. Yes, its early, but he could well have had sufficient sleep.
I'd suggest you look at shifting his whole day slowly (say over 4 weeks or so) rather than trying to get him to sleep 12hr over night. If you can push that first A time and shift the naps later, I'd keep the CN pretty short and try to do BT a little later.
So the way I would start that is to say the first nap happens at 3:30 or 9:45, whichever is later for a week, then move that to 3:30 or 10am, whichever is later and so on, until his day has shifted to a more desirable WU but that will mean a later BT.
Does that make sense?