MUFC_fan said;
I'm pretty sure MAN would get the 764 nod before EDI.
I'm sure your right as the 764 would require a runway extension before it could operate EDI-EWR with a full payload.
A CO 764 subbed for a 752 into EDI recently but it departed with a 752 passenger load so there was no problem operating from EDI's runway. The only practical alternative to 2 x 752 daily would be 1 x 772 but there's no space yet to park one on a regular basis at EDI. Maybe when the SE pier is complete and double sided their might be space but no firm details of the final layout have been announced yet
AFAIK.