1. Because lord only knows what's in that grime that made it on to your bike, leaving it on for that long could destroy your paint.
2. because having it covered protects from dust and or scratching while working around it. You want it breathable because otherwise it will trap moisture, which would be worse than dust and scratches.
3. Yes, othewise you'll get flat spots and basically have to replace your tires every riding season.
4. Don't know because I have the benifit of not having to stor my bike over the winter out here :waving:, but it sounds like you have it pretty well covered... maybe mothballs to keep the rodents away?
