How old are your kids? Usually kids age 8-14 will enjoy the place the most.
The waterpark area will likely be the focus for the kids, so I hope you don't have anything planned those days.
I suggest booking the character breakfast, it's quite good and the character selections is good. The mall also has character meet & greets with a variety of Nicktoons, but count on Spongebob and Dora to pretty much always be present. There is a food court (A&W, Pizza Hit, Subway, BJ's Coffee), a full service restaurant/buffet, and a straightforward buffet available for most of the day, and there's a convenience store and a Nick store as well. There's also a massive arcade and a 3-D theater (that costs money).
I suggest calling the hotel and seeing if you can request a room with a specific character, there's Spongebob, All Grown Up, Jimmy Neutron, Danny Phantom, Fairly OddParents, and probably one or two more characters, but Spongebob costs extra.
There's typically a list of activities available, and there are shows every night with Green Slime. There's also poolside shows with Slime as well. I'd also request a room nearest the Lagoon pool, that's the largest pool area and has the biggest play structure.
Every day at 4:45 they fill the bucket on top of the Lagoon pool structure with slime and dump it on the kids, which is quite a sight to see.
Characters rotate for appearances, but this is the list of characters that may be there during the days you're there:
SpongeBob, Squidward, Patrick, Dora, Boots, Diego, Pablo, Tommy, Chuckie, Angelica, Blue, Little Bill, Aang, Wanda, and Cosmo.