Sleeping in a morning or two is a good idea. However...................
On our trip last May we did things a little differently. We have always been the early risers. Up around 6, wake the kids at 6:30, get to that PS and finish breakfast before the park opens or be there for the start of Extra Magic Hour. We always liked the early start, get a lot done, head back for a rest and swim after about 3 or 4 hours in a park, then back to a park in the evening. We have done WDW that way on more than 20 trips over the past 12 years. It has always worked very well, even if there was a little mild grumpiness first thing in the am. In May I had the intinerary all set to do the same. Priority seatings in place, alarms set, wake up calls requested, but it all went out the window. Seeing as the DW is usually the first one up and rouses the rest of us, our plan fell apart a little given that she is six months pregnant and was tired. What happened each day is that we let the kids sleep until they woke up, and we slept in as well.
So what did we think of it? Well, we'll be going back to our early riser mode come December (as best we can with three kids, one of them being a three month old

). We found that getting to the parks late (we usually hit the parks around 10:30 each morning after breakfast) made it hard to get things done in the usual pleasant and efficient manner we were used to. It took us longer to get things done, and we found ourselves in the parks until at least 4:00 each day without a break. That cut into swimming time, wreaked havok with naps, and made for pretty cranky people by the late afternoon. IMHO, being in the parks for more than 4 hours at a time without a break (which the late riser mode kind of requires), especially during the hottest part of the day, is too much - at least for our family.
I agree that sleeping in a morning or two after a late night is a good thing, but as a general plan it didn't work very well for us. We missed the short lines of the first two hours the parks are open. We missed the refreshing time at the pool or having the kids nap during the hottest part of the day. We missed our relaxing evenings in the parks after everyone was rested, showered, and changed. While we didn't miss that initial morning crankiness having to get out of that oh! so comfortable

bed early, we would have loved to have not been cranky and tired all afternoon, running around trying to play catch up, and trying to fit everything into a shorter day.
Of course, what works for us may not be good for others. Good luck with the planning and have a great trip.