The UPH are great if you are staying less than 7 days and plan to spend every day at the parks, waterparks or DQ.
If you intend to spend a few days at Universal, go you will be paying for days at Disney that you will not spend in the parks.
If you want to take a day off from the parks and either relax poolside or do some shopping, you will be paying for days that you don't use.
The 12 day/11 night UPH will cost you $482.45 per adult and $386.60 per child. The passes expire at midnight on the last day of your stay.
For somewhere in the range of $310-$335 per adult ($250-$275) per child, you may be able to get a 30-day Fun in the Sun Pass. This pass gives you 30 days of unlimited admissions to all the Disney Parks, waterparks, WWoS, PI and DQ. You also get admission to Kennedy Space Center Visitor Center, Salvador Dali Museum, Edison-Ford Winter Estates, Miami Seaquarium, and Everglades Safari Park. Currently available passes also include breakfast vouchers. Ticket brokers do not advertise them on their websites. You have to phone them to see if they have them and what the expiration dates are on them. Try Ticketmania or ParamountTravel.
You could also buy APs. A regular AP does not provide admission to the waterparks not DQ or PI. They will get you discounts on those places. And you could possibly get a room discount with them as well. An adult AP is $392.99 and a child's is $334.41 (less than you will pay for UPHs). The APs are good for 365 full days from the date of activation. You could return to WDW anytime during that year and you would not have to pay for any park tickets!
Lastly, listen to your TA regarding
AAA. Unless you want to sign up for the other benefits of the program, it probably is not worth it. If you join now simply for the room discount and a better rate comes out later, you will have joined for nothing. If no other discounts come out for your travel period, you can then join AAA and she can apply the discount.
Don't be nervous. I know that it's overwhelming! So many hotel choices, so many ticket options! Just keep asking questions and we'll all try to help.