Lemon laws only apply if there are serious problems that the dealer cannot fix after repeated attempts.
Right now, the dealer seems to be working with you to verify the problems, and has not actually attempted to fix anything, so, no the lemon laws would not apply right now.
Of course you may have a lemon law case at a later date.
Some words about mileage.... virtually all cars will get better mileage after a few thousand miles (and in warmer weather!). Right now, the engine is new and pretty tight, so expect the mileage to improve, as the miles increase, the engine loosens up and the weather warms up. Keep track of the fuel used as the dealer suggests and don't assume the worst just yet.
Look here for more info.
http://www.fueleconomy.gov/feg/why_differ.shtml
http://www.fueleconomy.gov/feg/factors.shtml
http://www.fueleconomy.gov/feg/factors.shtml
http://www.fueleconomy.gov/feg/factors.shtml
http://www.fueleconomy.gov/feg/factors.shtml
Try backing up to a variety of obstacles to see if the reverse sensor is working properly. I can see snow banks may not work too well, but if it does not work for cars, buildings, child strollers etc, then there is a safety-related problem.