Let's break it down....if the plane arrives ontime at 4:50.
You get off the plane and head to DME area....about 15 mins, after actually getting off the plane. Then, if you don't have to actually checkin at the counter, it's right to the bus lines. You could be there for as little as 1 min or as long as 20 mins. Then, onto the bus...again, could be 1 min or 20 mins. The reason for these differences is that it all depends on where you fall in the lineup. IF you get to the bus line just as the bus is leaving, you will be first or pretty close to the front of the line....which means a possible 20 min wait for the bus.
Then, once on the bus...if you are first on, you could be sitting there, waiting for up to 20 mins. Or, you could get on last and be able to just leave.
Then, it's at least 30 mins to the first resort. If you are the last of three stops, you can add about 15 mins to that time.
So...
15 mins to level 1, DME checkin
5 mins to checkin
10 mins in bus line
10 mins on the bus, waiting
35 mins to resort
This is about 75 mins....the usual average time. So, that put's your resort arrival time at about 6:15. Checkin will take about 20 mins...now it's 6:35/6:45. It will take at least 30 mins to get to Epcot....wait time for the bus and the actual drive. Then, 15 mins to enter the park and about 20 mins to get back to WS and the restaurant.
As you can see...it's not going to work. You could take a cab to BW or BC and then walk to the restaurant from there, through the back door, International Gateway, but that will only cut off about 30 mins, tops.
I never book an ADR for less than 4 hrs after arrival at the airport. There are just too many variables.