Most users say that overwhite pants and appropriate upper camo work best in forested country.  In totally snow-covered areas, white pants and jacket work best.  They will get dirty after a while, and that is a plus up to a point.

Don't forget to wrap your weapon in some sort of disruptive camo.  Nothing shows up like a dull black AR in a snow field.

There used to be available hooded snow ponchos/capes––mostly German, with pine-boughs on one side of the reversible cape.

I've also seen some guy on youtube offering a very good snow ghillie suit.

Once in motion, camo is worthless.  Never forget that.

Noisy, and being waterproof, you will begin to build up internal moisture/sweat in no time with exercise.  They are sized to wear over light clothing, not winter outerwear, so if you're going to experiment, buy a way oversized unit.  Doesn't take much to tear them, either.

If one found one that fit, and one was in a static position, not moving much, then maybe the tyvek might do in a pinch.  Otherwise, it's not a good choice.  YMMV.