Hi there! Dont worry too much about winter driving, the HHR is fine. Im assuming you put snow tires on your vehicles, and I think you can even use studded tires as far north as you are.
There are some rubber parts in the front suspension that become noisy after a while, but its nothing major.
The main difference in going from LS to an LT is power seats. Also available on LT are options like alloy wheels and upgraded stereo. The 2LT has a better handling suspension, heated leather, 2.4L engine and chrome trim.

 

Welcome to the site!! I am from far-northern Wisconsin and I have all-season Michelin Hydroedge's on my HHR. My personal opinion is that the HHR is adequate in the snow, just not great. I use mine all the time in the winter, so maybe if I had snow tires it would be a little better. Mine is a 1LT, it does not have ABS or Traction Control. I am sure the ones with ABS and T-C are probably a little better. I can get around OK in bad weather, just not real "easily" I guess you could say. But my HHR is good enough for me in the snow department, it's not like I'm gonna go out and buy a Jeep tomorrow.