It should be beautiful! Friday high of 75, but It will be chillier on Saturday, with a high of 59 and some clouds. Definitely pack a jacket!
15-20 minutes by car. You should have plenty of time after the ceremony to get to the reception (and to stop for a drink or a snack in Old Town Scottsdale on your way, if you want). There are taxis, Ubers, and Lyfts aplenty in Phoenix, so don’t feel compelled to rent a car if you are coming from out of town.
Lots of construction on Thomas Road might increase your travel time to St. Theresa FYI!
You will pass through Old Town Scottsdale on the way to the reception and there are endless great bars/restaurants to stop into. McCormick Ranch also has a bar that will be open before cocktail hour begins. You’ll probably be able to catch the second half of the UA game!