We rented an umbrella at Typhoon Lagoon in May, and it was such a great buy! The umbrellas are located in the same areas as the cabanas. In our area, there were three umbrellas and 3 cabanas. There is plenty of space between, so you and your family have your privacy.
Our umbrella was #24, which we were told by a CM was the best umbrella in the park...he was right! It was in a roped off area (had to have a wristband to be there), and it was on an elevated beach that overlooked the wave pool...I watched the waves roll over people and relaxed in seclusion. The other umbrellas in that area (#23 and #25) were good choices as well.
I went back and forth about renting an umbrella at TL before finally taking the plunge...best monetary decision of our trip. It provided us so much value for the $55.