OP, while you're at it, run the numbers and compare the cost of a 2-Park Seasonal Annual Pass with the park tickets you've bought. (You'd have to pay the cost difference to upgrade your current tickets to 2-Park Seasonal Annual Passes.)
Assuming you're not visiting during blackout dates (FWIW, for 2019, there are no blackout dates in August for the 2-park Seasonal Annual Pass), the Seasonal Annual Pass can get you a significant discount on your on-site hotel -- generally more than enough to pay for the cost difference between the annual pass and standard tickets, plus you'll be able to return to Universal again if you wish in the coming months (again, subject to blackout dates), without paying more for tickets.
For example, my family paid $285/pp for 2-park Seasonal Annual Passes (before the price went up to its current rate of $298) -- just a few dollars more than any multi-day park-to-park ticket at that time. Thanks to our annual passholder discount, we're saving $134/night on our 4-night stay at the Royal Pacific Resort (paying $275 a night at the passholder rate, instead of the $409 rack rate for a standard room), PLUS by staying there we're each getting Unlimited Express Pass every day of our stay (at a value of over $100/person/day).
Obviously, it won't work for all dates and all people and party configurations, but do run the numbers! It's too early to tell now if APH rates apply to your dates, as they usually only come out 3-4 months ahead (the way you would check is to visit the loewshotels.com website, click "Book Your Stay," enter your details, click "advanced options," then "promotions," and enter "APH" in the promotions field). However, you can book the room you want as a placeholder (since you want Express Passes, you'll want it to be Royal Pacific, Hard Rock or Portofino Bay). Keep checking back on the Loews website. "Modify" your reservation to re-book it at the APH rate if and when APH rates come out, and THEN upgrade your tickets to Seasonal Annual Passes. (Anybody can book a hotel room at the APH rate, even if you don't have the annual pass yet -- you just need an annual pass in hand when you check in, in order to keep the rate.) If no APH rates come out for your desired dates/hotel, no harm, no foul - you can keep the tickets you have. Also note that only one person (preferably the one in whose name the room is booked) needs to have an annual pass, to qualify for the APH rates. Therefore, if you don't think you'd be back to Universal in time to make a second use of the Annual Pass but would still like to take advantage of APH room rates, you could upgrade to an annual pass just for yourself, and keep the regular tickets for your child.