It's a bit much for me, but that doesn't mean you can't do it and be fine. My husband and I did a redeye flight from WA state in 2012 -- We arrived at MCO around 6am just like you, and after dropping our stuff off at our resort (and a quick 1hr power nap since our room was ready!) we spent the day at AK...we were certainly fine for a while, running on excitement, but it hit us HARD mid-day and kind of messed up the next morning because we were just so tired (still made rope drop the next day, but were exhausted). We were only able to get about 1-2hrs of actual sleep while on the plane.
I do like most of avic77's suggestion of switching things around a bit and losing DTD in favor of AK or DHS (or back to MK or Epcot if you prefer). Moving your party night to Thursday would allow you time to nap if you're lucky enough to have your room ready or you can do DTD until it's time for the party which would be a bit more low key than doing Epcot while tired. The downside is that if you're really planning to be at the party until midnight, you will be beyond exhausted. No way could we have done a redeye then stayed up until midnight the morning we arrived.
I don't know, the more I think about it, I think your plan is pretty solid the way it is...arriving at 6am should give you enough time to make rope drop at Epcot (or close to it) and for the first part of the day you'll be excited and running on adrenaline so you'll be fine. If you find yourselves really tired in the afternoon, you can hang out in the countries and people watch (or ride the Ellen ride and nap! LOL) and just relax. You may get lucky and have your room ready for you when you arrive in the morning, or they can send you a text message when it is ready. Since Typhoon Lagoon is the following day, you'll get to sleep in a little bit (and you don't
have to get there at 10am if you decide you need a little extra rest) and recharge. With a trip that short, I would personally cut out the water park and just swim at your resort or have a regular park ticket to casually stroll through AK or DHS but if your heart is set on it, go for it!
We spent one day at Universal Studios/IoA during our trip and were able to do everything in both parks before 3pm, but it was in February during a low-crowd time and this was before the second HP area was built.
If your goal is to only do all of the HP stuff, you'll be fine for time and I'm sure you'll have time to do other things also. If you finish early this day, you can go to DTD if you want. I keep mentioning DTD because I think you'll have several opportunities to squeeze it in without dedicating a full day for it. We ultimately decided to skip DTD on our last trip because we aren't into shopping really but we had many chances to squeeze it in.
