Sounds like avoiding YYZ altogether, given the ongoing construction chaos, might be a wise option.
I'd opt for the YYC option on both legs. It offers the most civilized connection time and arrival time into LAS. On the way home, a 14:40 departure dovetails nicely with hotel checkout time, allowing a relaxed start to the morning after your last night in Vegas, followed by an ideal 1+45 connection time in Calgary. A winning combination.