You can try getting one annual pass (you can get a power pass as long as the blackout dates don't interfere.) Use code APH in the code box to check on hotel rates. They can be substantially lower at that time. You'd only need one pass.
Also, use other websites such as
Undercover Tourist, for tickets. You can often gets rooms cheaper through third party sites like Orbitz and cheaptickets. If you book through Orbitz, don't add the children since they charge extra through Orbitz but not through the normal website. Make sure, though, that you book the correct rooms.
Also, remember that the hotels that include express passes are deluxe hotels and are priced accordingly.
If you don't think you want express, Cabana Bay is a wonderful and cheaper option.
Peak times are really sparse for discounts.
With your family configuration, I'd consider the deluxe 2 queen room at the HRH since it includes a pullout couch and has lots more space.