You should be fine, I have run different sets on many a car but the fronts were always a matching set as were the rears. I had a set of snows on an old 245 that were 185/70/14 in the fronts and 205/70/14 iirc in the rear, both sets were different brands and I never had an issue. Used them for a few winters when I was living in Toronto. My 67 220 has continentals on the front and falkens on the rear, both all seasons. My 242 has falken zeix512's on the front and zeix912's on the rear. Similar but slightly different tread patterns, will be using a set of studded nokains for the winter, fronts are Hakka1's with Hakka10's for the rears.

I would definatly say do 4 snows, not 2 all seasons and 2 snows. The front end may not be the drive wheels but they sure are the steering wheels. Which is real important in the winter...