For 7 people, by far the cheapest transportation will be either renting a vehicle large enough to handle all of you + luggage OR private limo service. THe limo service is easiest. It costs about $90-100 for a vehicle, and if you check the internet there are some discount coupons available.
DCL transfers are about $30 per person each way. Sorry, I've never rented a vehicle big enough for 7 people, so don't know what the car rental places will charge. THey are about $40 for a car--there is no extra charge for drop off at the port, and they will shuttle you back (no charge). Of course, you then pay gas and tolls. They will also pick you up after the cruise if desired.
If you do the car rental, drop off everyone and the luggage at the port, then have 1 person return the car and shuttle back...much easier and saves all sorts of time.
Ok, 2 adults and 4 children--I get 6, not 7. On ship...for 7, you need a Cat 1 or 2 lower cabins.
Night before, I do Priceline. A 3* usually goes for $31-35, and they have free shuttles to/from MCO. Of course, if you were getting a car, you can do that and drive to the hotel. Technically Priceline rooms are for 2 people, but I've never had a problem with an extra kid...you would of course, need 2 rooms.
The most painless way to go is to get a room at the Hyatt. The Hyatt connects to MCO, and DCL busses service it. So...you would claim your luggage and make your way to the Hyatt. In the morning, you would put your luggage outside your room and go to the DCL bus. Of course, this option would cost you about $180-210 for the transfers (one way) plus over $100 for each room at the Hyatt for the night.
You really have to decide which is more important--ease or $.