Looking at your preferences, I'd probably lean you more towards the VW's you listed (Passat or Golf wagon). Both will offer very good fuel economy, good fit and finish, and the dealer will be motivated to keep you as a customer.
I probably wouldn't go for any Korean product if you plan on putting that many kms on it. I don't have much confidence in their products over the long term.
Mazda 6 would be interesting as you could get an extended warranty for the 7 years and not have to worry about the kms (as they have unlimited mileage on their warranties). It's a great car overall, fun to drive (bonus if you get the manual), great fuel economy, and there should be decent deals on them because they haven't been very popular.
If you wanted to go a bit cheaper, have you considered a new Honda Civic. Reason I say is you can load it up cheaper than a midsize, it'll have more space in the back seats than the Sportwagen you're replacing, offer excellent fuel economy and reliability.