You can see the Water Pageant from the resort boat launch, sand 'beach' between the boat launch and bungalows, and even the Volcano Pool.
Yes, you can mobile order the 'Ohana bread pudding from Kona in the
MDE app to-go. You can also order it at Tambu Lounge starting around 4pm, but it isn't to-go from Tambu Lounge. You can take the plate and eat it outside of the bar area, but it's not as simple as Kona if you wanted to bring it with you outside to do something like watch the Water Pageant.
IDK the age mix of your party, but if you have kids there are fun recreational activies like a campfire, outdoor movies, crafts (make your own lei, paint a pineapple, etc). For the older crowd Tambu Lounge (Lapu Lapu is great! I can't tell you the amount of times I have been asked where I got my 21+ pineapple drink) and Trader Sam's are some of the best bars/lounges on property IMO. Captain Cook's also has some of the most unique quick service on property. Tonga toast, pulled pork nachos, and Thai coconut meatballs are extremely popular. You also have Pineapple Lanai which serves Dole Whip and some seasonal specialty flavors/treats throughout the year. Captain Cook's has a nice outdoor patio by the pool where you can easily eat your QS, to-go food, or Pineapple Lanai treats. The second floor of the lobby gets pretty crowded between Kona, the monorail station, and 'Ohana so the first floor may be a little more "quiet" if you wanted to sit and relax inside. You can easily walk to Grand Floridian with the connected path if you want to check out the neighboring resort and what it has to offer. You can also walk to the Transportation and Ticket Center and jump right onto the Epcot monorail without having to transfer which is convenient.