Re: Toyo Celsius, Nokian WRG3, Continental TrueContact
Just to chime in late on this. My wife and I are about to purchase a new vehicle, and the Sienna is one of three on the list (why I registered here.)
As for the tires, I am on my second set of the TrueContacts on our 2007 Odyssey EX-L. On this van previously, we had the ComforTred Touring, Defender, Firestone Winterforce, and some Falkens (I forget the model).
For us, the TrueContacts are worlds above the others. The tread-life is my only gripe. The overall grip in the light snow, down pouring rain, and dry is MUCH better than the Goodyear (comical wet grip), and a descent bit better than the Defenders. We only get about 40k miles out of a set, but for the added security of what is most important when hauling around the family (great traction in all weather) I don't mind replacing them more often. The Defenders were a joke in the slush. My ComforTred's that were worn down (had 48k on them) to the tread wear indicators had better control, response, and gripe than the Michelin's did when new.
For where you are, I think you went with the best option. If you are looking for a tire to use in a less severe snow climate, the TrueContacts and even the Altimax RT 43's are a very good option. I've had great success with those tires on other vehicles.
I hope you have many miles of safe use with those tires.