Addressing your first question it kind of depends on you and your set up. You can get tires that have studs that are made for Ice and snow or you can use just really knobby tires. You are on the right track engine wise. I am guessing you want it relatively reliable (who doesn't?) knowing very little about you and your situation I can't really give any solid suggestions. No set up is perfect but there are a few that are much better then others.
Read up and ask questions. Every one is very friendly and you are in the right place