I wouldn't count on the aircraft being the same one. A WS insider might be able to tell you more precisely of it normally is. I've been on same plane service more than once where for whatever reason we switched planes anyhow, so it can happen in circumstances like that.

40 minutes in YYC is plenty, however, as the gates are very close together. I've had 30 minute connections that have worked out fine. Of course, delays can happen but that could impact you even with a longer connection. WS has had a rather poor on time record of late, but historically they have been very good so personally I don't have any worries when I fly them about being late or missing connections. I recently flew YQR-PHX on WS and then connected to US to SAN on separate tickets and I truly had no worries that WS would get me there in good time (and they did). I wouldn't have done that routing with UA or AC. Maybe I'm foolish...