how large is the property?

I think a good architect can work out a solution that brings lots of south light into the house. No you didn't make a mistake. BTW: The east isn't as big a problem unless like me, you're not a morning person. LOL. It's the late afternoon west sun that can be a problem and that also depends on what part of the country you're in. In FL where I am, it's a big problem. If you're in Alaska or ND, I'm guessing it's less of a problem. :)

I think the lot is big enough that an architect can work with the property, unless there are a lot of architectural restrictions that come with the lot or you envision a sun filled backyard with a pool to use in the afternoons. If you want a sun filled pool area you'd need to put the pool in the front yard and re-orient the house accordingly. I see snow on the ground that might not be a major factor. You might want a design that includes some clerestory windows that bring light in from the Southwest into the rooms on the back side of the house that face Northeast. An architect who is experienced with passive solar design and design to accommodate prevailing winds/snow accumulation would be a good choice. Unfortunately if the lot comes with a lot of architectural restrictions you might have less ability to design a home that works well environmentally with the lot.

Agreeing with cpartist. Depending on orientation, you may also want to take tall trees and vegetation into consideration since these could be used to your advantage or otherwise while deciding on orientation unless you have a view lot, in which case one would expect to clear trees to open up views. There are too many unknowns at this stage. It would be wise to visit other properties in the area to get a feel for what works or may have worked for others. There's nothing like talking to a local architect who may provide a sketch for a nominal fee.

I've been to New Brunswick. I think in the winter you'll welcome that western sun. Having said that, you'll still want to shade the west side well for the summer sun and also orient the majority of your windows to the south.

It appears you will enter you site from the west. With that large a lot and with all the trees which are existing, almost any sort of house can be designed to fit your property, your access direction and be an effective passive solar house with the major public and open spaces oriented southerly.

You site is very buildable.

What you need is an experienced and talented architect who know how to do all of this, while meeting your aspirations, functional needs and budget.

My advice: start identifying and interviewing architects whose practice involves a major concentration on custom single family homes.

In Canada, there are also "architectural technicans" who are not licensed architects. I can't speak to their ability or expertise, but architects I do know! :-)