Thanks OP!
Booked BOS-YYZ-LHR // BRU-YUL-BOS on the big O. Confirmed and ticketed within 10 minutes. AC website shows business class, as does the seat selection tool. I give this a strong possibility of sticking, given these fares are "very good", but not "insane" (not an obvious mistake).
Traveler 1: Adult $1,127.00
Traveler 2: Adult $1,127.00
Traveler 3: Infant in lap $742.44
Total $2,996.44