I've been to Discovery Cove twice. I haven't been in a few years (need to go back) but it used to include a 7 day Sea World ticket. Our last visit they also offered us an option for Busch Gardens- but we opted for Sea World.
You can do DC, get Sea World in and have a great time. Note, you still have to pay for Sea World parking if you use those Sea World entitlements. Discovery Cove used to sell a parking pass that was a reduced price- like $15 for a whole 7 days of Sea World parking instead of regular gate price.
So Discovery Cove: all food/drink included (they used to include beer/wine in that price- do they still?), no parking, free use of snorkle equipment, free photo (do they still do that?) and of course a capped enrollment per day.
My kids really didn't like Aquatica. Check to see if Discovery Cove offers an Aquatica option.