"Lass" is just short for "lassie", I think. It's an Irish or Scottish thing. Maybe both.
Update on the farm: it's now winter of the first year, and my wedding is coming up in just a few more days. No one is actually talking about it, including the fiance, but I know it's coming thanks to the manual. It snowed a bit one morning, and a weird sasquatch-looking guy has been walking around and mumbling. Also, I bought a pond, which goes in the pasture and is apparently used as a swimming place for ducks, except I've never seen a duck and can't buy one. So I don't know the point yet.