Separate rims are the way to go. Using separates allow you to flip all-season to winter and back again without having to risk damage to the tire or rim with repeated changings. It's also faster and most likely less expensive.
I don't know about those Nissan rims, although it sounds like a pricey option to me. Have you considered a tire specialist garage with 3rd party steel rims? They might be cheaper.
As far as the tires go, I considered the Toyo but decided having a higher speed rated tire would give me better value. I went with the Yokohama Geolandar I/T+ for my Sorento. No snow yet, so I can't write up a review!

Morty from Tire Trends can fill you in on the Hankook tires.