My fiance and I are getting married next year and I don't know how far in advance of the wedding to file the I-129... how long does the total process take? Also, can he get an EAD from the US consulate in Montreal?

Processing times vary widely, depending on the Service Center you are using, for example: Vermont may take 30 days and Nebraska 180 days. It will, however, take several months to process because there is more than just the initial approval - it has to go through the National Visa Center and the foreign Embassy. Our application, start to finish, will take approx. 9 months and we filed through Nebraska.

No he cannot get an EAD through the US Embassy in Montreal it has to be issued in the US