You will have to get your own luggage when you arrive at MCO but not going directly to WDW. I think that if you stay at the Hyatt, right at the airport, they may have a system of taking your bags from your room and getting them to the DME baggage area for you. But other than that, there is no way for Disney to handle your luggage if you aren't going directly to your resort.
You would have to claim your luggage when you deplane, take the luggage with you to the hotel for that first night, then take it with you, back to MCO, in the morning, if you are riding the DME bus to your WDW resort. Your bags would then go underneath the bus you are riding on.