All three resorts are wonderful! I am a huge fan of Coronado Springs and the construction should be finished by October 2019. However, it isn't a sure thing by any means and delays for completion dates seem to be common. The safe bet is POR, with its beautiful grounds, walkway to POFQ and boat to DS. You also have the horse and carriage ride, surrey bike rentals and access to two themed pools (POR and POFQ).
Personally, I would probably play it safe and choose a stay at POR. (However, if CSR is completed prior to your dates, you could always consider a switch - subject to availability, of course!).
a couple of budget thoughts:
One thing to watch for are discounts. If a really good discount was available at any one resort, I would be inclined toward that resort.
Also, while all three are lovely, they are all large, sprawling resorts. If you want to be near the dining, check in, gift shops etc, a preferred room might be worth the extra $$$.
SO, availability of a preferred room, coupled with the price, would be factors for me in deciding which resort to choose.
Enjoy!!!