I'm only speculating and probably shouldn't say anything at all, but I highly doubt U2 will perform 4 shows in Alberta or in both Edmonton and Calgary...at least not on the same leg. I could be wrong but if I were the promoter, it wouldn't make a lot of sense to me. Here's why:
Growth or not, Edmonton and Calgary are still very small cities for U2 at just over 1 million a pop. Since u2 exploded on the JT tour, historically very few cities of that size get 2 shows, much less two small cities in the same province. The cost of travelling around Alberta for the markets you would reach is very high.
Tours are not only about selling tickets, they're about selling albums. Tours can be lucrative but they are also very expensive. Albums are low cost by comparison and the purpose of any tour is to get fans in the building, see the show, buy a t-shirt, create a media spectacle to get people to go out to buy U2 albums. After all, you can sell more albums than there are seats. This is where I see the biggest snag for simultaneos Edmonton, Calgary shows. Alberta's total population is not even that of Montreal. The time (2 days) and cost of packing up, taking the customary one day break and traveling to the second venue in order to reach a million person market is enormous.
The only chance I see for both cities to get shows is if U2 go to one venue on the first leg and then the other on the third when they return to North America. I guess we'll see.
Jon