You can check for AP hotel rates for your dates now, you don't need to wait until you have an AP in hand. You can book the room now too, which would be a good idea since the rates & availability do change. Note there is an extra adult charge for more than 2 adults in a room, at the EP hotels I believe it is $55/night.
The main con right now is that the AP doesn't include any
Epic access. So your AP holder would need to buy additional single day tickets for any Epic days.
In Aug you shouldn't have to worry about blackout dates and parts of Aug and Sept are Universal's passholder appreciation days which have some extra AP benefits, like food discounts for even the lowest tier AP.
The other "con" with an AP is the urge to add more trips since you already have admission... Right now there is a 3month free promotion, you can buy the AP now and wait to Aug to activate, and it would be good through next Nov. An excuse to come back for holiday happenings...