We went to AK back in September and were able to ride FOP 6 times and NRJ 3 times in one day, with 2 people in our party. Here is how we did it:
We got to the park 1 hour before official opening. Keep in mind that we went on one of the least busy days of the year, so you may want to get there even earlier. We rope dropped FOP and then were able to do NRJ with a 20 minute wait right after that.
We then did all the other rides in the park while everyone was getting to Pandora "early" (KS, Everest and Dinosaur). We then went back to Pandora to ride NRJ with the fastpass I got at 11am.
The rest of the day is fastpass. It is crucial that you book your first 3 fastpasses as early as you can. So if the park opens at 9am, your ideal fastpass times would be 9am-10am, 10am-11am, 11am-12am. As soon as we used our third fastpass we were constantly refreshing the app for FOP. By doing this we were able to get 4 more fastpasses for FOP and 1 more for NRJ. We spent the time waiting for fastpasses by exploring the land, eating at satu'li canteen (which I HIGHLY recommend) and pongu pongu. We were also able to fit in Festival of the Lion King, Nemo and Bugs life when the wait for the next fastpass was longer.
Finally we ended the night by watching Rivers of Light and as soon as the show ended we rushed back to Pandora to get in line for FOP right before the park closed for our 6th and final ride.
Although refreshing the app all day is a bit annoying, it was so worth it. FOP is one of the best rides on the planet and you need to ride it at least twice since the first time you ride you are guaranteed to have sensory overload. The only other downside was having to sit through the preshow 6 times, but saying "and, uhhhhh, fly" all day with my girlfriend made it worth it.