This thread mentions flights from EDI
to Florida. I doubt it will happen this year though as it is a bit late to be launching this and trying to get bookings.
How much longer does the Air Transat contract run for, for the flights to Canada? They could replace the A310's on the flights to TOR, etc. that you can book on http://www.globespan.com.
Not really sure that they need 3 763's. That is a lot of seats, although in the peak season they could stick one on the Spanish holiday routes.