Based on my habit of doing exactly this over the years, if they think you can get it in time they will FedEx it to you.
Otherwise, they will send you the regular e-mail confirmation and hold your package for you at the check-in desk in your resort for you to get upon arrival (the coupons, etc).
As for Magic Express, you can totally use it without the luggage tags so long as you have alerted them of your flight information. You will have to be able to describe your luggage to the ME check-in person, and give them your checked-luggage tags from the airline so they can find your stuff. When this happens to us, I always tie some strangely-colored ribbon on the handles of our bags to make it easier. Everybody has a standard, black, wheeled bag - but very few have one with pink-and-orange striped ribbon or blue plaid ribbon or whatever on it.