I was a tour guide for my brother-in-law's family last year with one day at each park: EPCOT, SeaWorld, and both Universal. The way I handled it was made a list of all rides, shows, and activities. I went to each person about what was a not to miss, good if we had time, and don't want to waste time at. For Universal it's important to go to the non express rides early. We had two kids that were split between coaster riders and non riders. I go all the time so I stayed with the non rider whenever needed. HP express is not worth the line if it's long; I'm sure there's video on
Youtube. Studios has a lot more to see than IOA unless the kids are really young. I also made it a point to let the kids know that as much as they are going to want to stand around and look at the HP area we needed to ride the rides then loop back around in the afternoon to go in the shops and take pics when the lines are long.
Order we ride:
Studios: Gringotts, Simpsons, RRR, Transformers, Mummy, MIB (if the line is not long you can go in child swap and ride again), then whatever else you might want to see. I don't go to the kids area. Shrek is a theater show similar to Mickey's Philharmagic. Minions is not worth the wait unless you have express so I'm glad you do. I personally don't often go to the Horror Makeup Show since I've seen it so many times but it's cute to see if you have time. Again I'm sure it's on Youtube to give you an idea. The animal show is cute. Jimmy Fallon will be open by then so we don't know yet if that will have express, what the lines will be like, and how fast it loads. The night show is something to do if you have time. They basically project old movie clips onto dripping water w/ fireworks and music. This is a good time to get in line for one last ride on Gringotts or just look around in HP since everyone will be leaving or watching the show. You can get some good pics at this time.
IOA: HP castle ride, Kong, Hulk, Jurassic Park, back to HP for Hippogriff and Dragon's Challenge. The Suess Land is cute but if the kids are old they won't be interested in the rides. You can gets pics with characters and the stores are fun to look at. Not as much to do here so I would pick this park if you only have half day. Also no night show here. Again don't spend time looking around until you've ridden all the most important rides.
Download the Universal app on your phone. Very useful and you can get an idea of ride time before you get to the park since it works even when you're not there.
Have fun.