Direct Seeding Thyme in Lawn?

I'm very curious to have your help with my question. We live in Chelsea, Quebec , just over the border from Ottawa (zone 4). We have quite a large lawn (.75 acres) that is currently a mix of grass/clover/weeds. I'm not a fan of mowing, and I would like to transition to a thyme lawn (I think wild thyme as it seems to do well here).
Is it possible for me to direct seed right into the lawn we currently have, or do I need to remove the entire lawn and start from scratch (I hope not!!). If I grow plugs, can I plant them into the lawn that is already there or will the grass kill them?

Wild thyme seeds are so tiny that it is unlikely that they would germinate and develop in an existing lawn. So, yes, you would have to remove the existing grass in order to sow a lawn of wild thyme.
Plugs may fare better. We have not tried planting plugs in an established lawn, but we know that wild thyme competes very well against grasses and weeds in lawns. If you plant plugs throughout an existing lawn you may well get the thyme to form a solid mat within a few years. How quickly that happens depends on many factors, but the most important is the density of plugs planted in the lawn. Depending on your budget you can plants plugs as close as 10 cm (4 inches) or further apart. For each plug you need to clear a small area of grass – say 10 cm in diameter – and plant in the centre of the clearing. You need to mow the lawn 1-2 years until the wild thyme overtakes the grass.
Although we are pretty sure that the plug idea will work, we have not actually tried planting thyme plants in a lawn, so we cannot guarantee that plugs will work.