If it were me, I'd take a cab from the CBR over to the WL for breakfast, otherwise you'd have to get an early bus to the MK and then from there take the boat over to the WL. You'd have to be at the bus stop by 6:15/6:30
After your ADR take the bus from WL over to Epcot.
If you don't want to take a cab, I'd recommend reconsidering where you are having breakfast that morning. To me, it seems like a big hassle to be up at 5:00 - 5:30 to be able to go to a breakfast reservation.