Can you exit and return to the park on the same day

Sure you can check out the fireworks

Absolutely

If you have a park hopper pass you can come and go as you please. It's well worth the extra cost.

Yes, you can re-enter the same park after leaving. If you want to go to a different park, you'll need a park hopper or separate ticket for that park.

Yes you can with your same ticket

Yes

You sure can!

Yes, depending on the ticket you have. If it's a single day ticket, you must return to Epcot if that's the first Park you entered. If you have the ParkHopper option you can come and go as you please.

Yes if you have annual passes