Mutsu is not the easiest apple for me but it may well ripen there. Frost does not pre-empt further ripening, very hard frost does (around 26 for tender varieties), but how much cold an apple can take varies from variety to variety. Z5 may be the new Z6 anyway.

Japanese types tend towards low acid, high sugar. Mutsu is tasty if you like this sort and also a great cooker as far as holding texture and adding its own sugar to the recipe.

Madison isn't that much further north than Chicago. I've had no problem ripening Enterprise until mid October, which it needs, and I just got an October Fuji. I'd take the bet.

Thanks for the advice, I think I will try it!