Magical Express transportation is available around the clock.
As during the rest of the day, each Magical Express coach from MCO to WDW normally stops at a total of 3 or 4 resorts. During the day, when Magical Express is busy, the resorts are usually in the same area of WDW. But late at night, the resorts can be anywhere at WDW. (The good news is that they dispatch coaches based on demand, rather than waiting to get enough guests going to the same area.)
With a 7:00 a.m. departure, your Magical Express pickup time will be around 4:00 a.m. If you use a towncar service, you can get an extra 30 minutes of sleep because your pickup time would be around 4:30 a.m.
Magical Express inbound luggage transfers are offered for flights arriving at MCO between 5:00 a.m. and 10:00 p.m. For flights arriving after 10:00 p.m., you have to claim your own bags at baggage claim and take them to the Magical Express coach.
On you departure day, you won't be able to use Resort Airline Check-in because it doesn't open until 5:00 a.m.
Early and late flights are often cheaper than flights at more convenient times. But there's a reason.