Yes, the best sailor of the bunch, and likely the best made would be the S2. That said the one in the best shape is likely to be the best boat. 3 grand on the Hunter with no electronics, and not well maintained sounds like a LOT of money. This is off season and so unless he has brand new sails and rigging
I would think that boat is at best 1500, and likely and expensive prospect if the bottom has not been painted in 5 years. Even on a lake you should do it every few. Not that painting a bottom on a boat that small is going to be that expensive, but if they have not done that what else have they not done? I know there are a few Lake Norman sailors here so perhaps you could get someone here to look with you. I don't think in this size range and price range it makes sense to get a survey, as it will almost be as much as the boat.
As to maintenance the smaller and simpler the boat the lower the maintenance cost. Depends on how handy you are, it really is the labor that will kill you if you have to pay someone to do simple things.
Lake Norman sounds like a nice place to have a boat. I grew up going to Lake Lure every summer for a few weeks. We loved the area, it is so beautiful. Though Lake Lure does not seem to have any sailing at all, at least not back when we went.