I work at Typhoon in the merchandise store. I don't get out into the park hardly at all, so you might actually get better information from TL guests who frequent the park. But, I'll share with you what I think I know. There is a section at Typhoon for little kids (under 48 inches tall, I believe). There is some shade over there along the outskirts of that area. There is also some shade near Crush Beach (a beach area near the water coaster, Crush 'n Gusher). Crush Beach is about as far away from the kiddie area as you can get. There are pockets of shade around the park. But, quite literally, the shade moves throughout the day as the hours go by.
The only way to ensure shade is to rent a premium space -- an umbrella and chairs for four people maximum; or a cabana that holds six people at a certain price, but can accommodate up to 10 people with the extra four people paying extra dollars. Just like hotel rooms change prices throughout the year, the premium space rental fees change throughout the summer. The umbrella spaces are reasonably priced. The cabanas can be expensive...although, who am I to say what is expensive -- I guess that's an individual call. But, the cabanas come with furniture, a locker in the cabana, an ice chest with all the bottled water you care to drink, refillable soft drink mugs, towels, and an attendant who will get your food and drinks for you.
There are two what I call "restaurants" at TL -- The Leaning Palms and Tillie's. Both serve the standard sandwiches, wraps, salads, etc. I think Tillie's has a fruit salad. And there are other food places around the parks -- pastries, funnel cakes, ice cream, as well as a bar, should you wish to enjoy an adult beverage.
If you don't rent a cabana, I highly suggest you rent a locker. Do not leave anything of value on a beach chair while you run around the park. Umbrella and cabanas can be rented at the main merchandise store or towels and lockers can be rented at High and Dry Rentals. You will encounter both places as soon as you walk down the sidewalk into the park. If you are staying at a Disney Resort, you can bring towels from there if you'd like. Or bring your own towels.
So, that's what I have to share. But here is my disclaimer -- the water parks are currently going through their annual "refurb." Since Blizzard Beach closed in October for it's refurb, and while Typhoon is closed starting in January, I am deployed to Hollywood Studios. As such, I have absolutely no idea what changes will be made at Typhoon and what will be different when I get back there.
Debbie
I should add, if you think you'll want to rent a premium space, do it in advance by calling 407-wdw-play. In August, if you wait until the day of your visit, you'll be out of luck.