Getting a phantom room is cheaper than buying express passes seperately. I already priced it out for a Royal Pacific room. My husband thinks an extra $344 for a room we won't even stay in is a bit much so that we don't have to wait in line. I'm not sure, as I think we won't want to tour in the middle of the afternoon and will try to take a break back at WBC and go back in the evening.
I have heard August described as "surface of the sun hot". And very few schools will be back in session at that point. You want to be on nice breezy rides in air conditioned buildings or with the wind in your faces. You don't want to be standing in line for an hour for each ride.
344 extra for 5 people to get UNLIMITED express pass over two days works out to almost nothing for each of you. Your time is valuable. If someone said to each of you "would you pay $34 per day to get minimal lines for almost all rides all day?" that would be amazing! And if they threw in access to an onsite hotel room and all benefits (except for sending purchased items to the room...can't do that with a one-night stay), you would wonder how you won that lottery!
The only problem is if I book it for one night, we wouldn't be able to use it as a break spot the second day due to it being check out day.
Take a small bag of stuff with you for each person. (listen to George Carlin's rant about vacations, and taking smaller trips while on vacations, and even smaller, to know that you're not the only person who has ever done this.

) Whether or not you actually sleep there that night, bring changes of clothes, bathing suits, whatever you might need to help you feel more human each day. That second day, make your rest time at the pool! ANY of the pools on property are OK, because Universal allows pool-hopping. You would need to go back to RPR to get the bag out of Bell Services to get what you needed for the pool, then go to the pool of choice, then just change in the pool bathrooms before heading back.
Do make sure you know the park closing times. They close a bit earlier than WDW does most of the time, so I want you to plan accordingly.
Once you do book that one-night hotel stay, do it room-only (I personally book directly through loewshotels.com), and check back. Prices change, and if you find a lower price, you can call to change it. And don't be afraid to check out HRH and PBH too! They can sometimes go cheaper depending on solar storms (just a way of saying "I don't know why but sometimes it happens").