Personally, I would get the Leaf.
Your comfort will be much higher with the fast heating.
The drive will warm the batteries a bit and i imagine the Leafs temperature management will do the rest.
Invest in a fast charger if you can, so that the batteries don't have to be heated all night during a slow charge. And the percentage of the charge that is consumed by the battery heaters whilst charging would be less. Fast charging would also assist by raising the battery temperature more than a slow charge.
With such small range requirements the energy lost on heating the batteries shouldn't cause an issue other than electricity cost and longer charging times. Another reason to get the fastest charger possible.
After a dozen years the battery pack may be on it's last legs. But if it's last legs still give you the miles you need each day then the battery pack doesn't need replacing.
Insulating the batteries sounds like a good idea for areas that experience frequent extreme cold weather. Especially if the batteries (and cabin?) can be pre-heated while still plugged into the charger and so not reducing the range. If you aren't charging at work then the opportunity for pre-heating the batteries for the return trip wouldn't be there.
Then there is the safety aspect. With your anti-idle laws, the ICE vehicle basically has no heat on the short trips you make. So the windows would be misting up all the time. Not ideal on icy roads.
So in your comparison calculation you need to add in how much you value your comfort and safety.
If it was just a few dollars a week difference between sitting in a freezing car battling poor visibility or sitting in heated comfort with clear windows. I know how i would like to start my work day.
