Lemon & Creeping Thyme for a Lawn in Zone 2-3

I am located in East Central Alberta, Canada, SE of the city of Camrose - closer to the Alberta/Saskatsewan border; our growing zone varies from 2-3 depending on our winter temperatures and snow covers. This area we are in has beautiful sandy loam soil – we are in the process of renovating our home and yard to be low maintanance. I am looking for a lawn replacement herb for this purpose, our yard does get various amounts of shade and sun depending on were the sun is at any giving time – morning, afternoon, evening etc. (we do not have any complete shade areas).
I like the idea of the Lemon thymes for aid in bug repelling, but I am not sure that they would winter ok with a sometimes low snow cover, plus they are slow growing. Is there a possible mix that I could use in order to have a good ground cover and still get some bug repelling properties?
Occasional mowing and watering is not a problem. We do have a heavy natural growth of wild Wormwood Sage (Artemisia sp.) in our pastures, which I have also considered using.

You would have to use purple carpet lemon thyme as this is the only thyme I know of that survives in zone 2. Who would want another thyme when they can use this beauty! This plant is not available as seed so plant plants on six inch (15 cm) centers, weed and water faithfully the first year and it will make a lovely carpet. If plant cost is a problem, start with a few plants and gradually increase the size of your thyme lawn from cuttings. Mulching for the winter will cut down on winter kill during low snow winters.
Another option is yarrow (Achillea millifolium). Yarrow makes a beautiful ground cover for lawns, is very hardy, withstands mowing, and can be started from seeds. Yarrow is a key component of our "Take-A-Hike!" bug repellent, and was traditionally used by the people of Lapland to repel mosquitoes. If walking over a yarrow lawn doesn't help discourage mosquitoes, you can do what the Laplanders do: rub some fresh leaves on the skin.