I think you are making yourself needlessly worried. I saw your plan on the other thread, and you are going to be just fine. The "mess" that the media reports is generally overblown. Going at that hour on a Sunday morning, Philly should be pretty peaceful. Most of the reports pertain to peak hours and of course, the bad days, when it is crazy there. I have been in & out of Philly numous times, and only once did I get stuck in a bad line, and that was at 5:00 pm on a Thursday, a notoriously heavy business travel day & time. The time you are leaving MCO ( is pretty busy, esp. in the summer. When we were there at Thanksgiving, they seemed to have everything running well, but as with all things airline, that can change. Give yourself lots of time, breathe!, and you'll be fine. If you have extra time at either airport, the shopping is quite nice!
Just get your boarding passes the night before, check your bags curbside (assuming they are open, if not you'll have to go inside) and proceed to security. If you have trouble with US Airway's on-line boarding pass system, do not panic, it can be a little quirky. Just go to the kiosk with your credit card (does not have to be the one you used to buy the ticket). It will know who you are & you'll follow the prompts and be on your way in no time. BTW - you can check luggage at certain kiosks (which look just like ATMs and are lined up next to where the human agents work in PHL).
Have a great trip.