assuming you don't run into wheel well clearance issues, which is doubtful, there is nothing wrong with having a little more ground clearance in snow.
I'd use them, and change only if I discovered an issue.
Stick with recommended size....225/50 have around 8.5% larger circumference, they may not clear fender lining at full lock, car will be another half an inch taller and you will change effective gear ratios...yes it is wise to keep circumference as recomended
Q4 sits higher than RWD or QV. That may or may-not translate into more clearance for the tire.
At full lock and compression there have been issues with QV front tires rubbing on some cars even with the stock tires and suspension. QV front tires are a little wider and a little shorter than your Q4 tires.
Perhaps your tire installer will do a trial fit for you? If so, please let us all know if they will fit. I have been eye-ing fitting 245 40R19s but am also concerned about the clearance.
Front Tire sizes that are known to fit without rubbing (based on forum member reports):
225 40R19 (OEM size)
255 35R19 (probably rubs on QV or lowered vehicles)
245 35R19 (QV size, see note above)
225 45R18 (OEM size)
225 50R17 (OEM size)
The rear wheel wells should have clearance for small tire diameter increases (the car is rated to allow installation of chains) and fairly large tire width increases (with appropriate wheel change).
One concern is that in at least one report with 265 30R19s on the front of a lowered QV, the tire rubbed hard on a spot of the wheel well that has a major wire harness against it on the other side. Tire rubbing wire harness == disaster. See Call Me Al's posted diary of his performance enhanced Giulia QV.
They have been pretty accurate in the past from personal experience. America's Tire/Discount Tire also has been very flexible when it comes to replacing the tire with a different one if you are not happy with it for some reason.
Your mileage may vary, so it goes. (Should have noted that....)