This discussion has diverged ... but to get back to the original question.
I usually found that when trekking in deeper snow, I mostly just needed some good waterproof pants. The outer shell should be waterproof. And under that I usually wore some warm fleece pants.

The important thing is to make sure you have a good set of gaiters ... otherwise your socks get soaked from loose snow that creeps into your boots and melts.

These comments don't apply if you are walking around on snow that is well tramped down. If the surface is firm ... no problem. But if you are postholing - that takes a lot of work and your gear needs to be waterproof.

Have fun.

cheers,
Pete 2