Can I exit and then enter the US with two different passports, using?
Technically yes. Legally, no. You should use the same ID to enter and exit each country on your itinerary. That said, the ticketing system at you local waterpark is more sophisticated than the international passport system. I have, on occasion used the wrong passport to move through Europe, Canada and the US with no consequences. It is important to keep close track of your entry, transit and exit stamps. If the customs guy is looking for your entry stamp and it's in a different passport there WILL be complications; and not the good kind.