The 2012 Subaru Impeza wagon with the 2L and auto gets 27 city and 36 highway. Mileage with the manual is 25/33.
I really see little need for a trying to combine economy and awd. In my experience, if you get awd for poor conditions, you need reasonable ground clearance. A low slung awd high gas mileage regular Impreza or Legacy may look good on paper, but with their limited clearance and usual floaty lower profile tires, you will get hung up pretty easily. That’s what happen to me with the regular Legacy…it improved when I stuffed the tallest tires I could under it, but can’t be done as easily with later models. An Outback it isn’t.
The best way out for me if you want economy and awd is…get a used higher awd SUV or a 4wd truck that has other uses, a cheap used compact and equip both with snow tires. Neighbor had a low awd Audi …it was nearly useless as it seemed to get stuck on our road all the time when the snow was deeper than a few inches. AWD and 4wd are really only as good as their clearance. If you want them for their better handling, fine. Otherwise, get something higher. I am very skeptical about a small light awd and their deep snow performance.