Expire is not really the right term; but effectively yes. In general a cheque older than six months will be considered stale-dated and will not be honoured. Reference the Canadian Payments Association FAQ.
SKYACTIV is a brand name for a series of technologies developed by Mazda which increase fuel efficiency and engine output. The initial announcement of the SKYACTIV technologies include new engines, transmissions, body, and chassis, which appeared in Mazda products from 2011.
The Edge relies on Mazda 6 architecture, and the Mazda uses some Mazda 3 and Mazda 5 suspension layouts as well as the Mazdaspeed 6 engine, but much of it is unique. The windshield, for example, has a 66-degree angle, making it the raciest glass in the segment.