Have a great time!! Your kids will not be too young. They picked kids that age for the games at the pool as well as the Nick Live Show. In the Nick Live Show, it is two teams against each other. The teams can be up to four people so it can be you, the kids (and the hubby?). We had only three. The captain of the winning team gets slimed. The captain of the losing team can pie himself or choose a teammate to pie. At our game, we won and my son (age 8) got slimed. The kid on the losing team pied his mom and smooshed it all over her hair!
The Who Knows Best? Show is probably better for the older one. It is a Newlywed type game- they ask you questions about your child and then they see if your answers match his/hers.
They are going to have a great time. There is face painting in the Mall. It costs $1-$5 depending on what you do. I had them paint a character on their arms and it was only $1 each.
Please heed my advice about the Character Breakfast. NOT worth the money. The same food is available for cheaper on the other side of the Mall without the characters. ($65 for the four of you at character vs. $25 at the other restaurant). The characters at the breakfast walk around the mall afterwards and take pictures and stuff. I love the Nick Hotel and they are doing great in lots of areas, but Disney does its character meals soooooooo much better. Might want to hop over to Disney for a character meal. (We did dinner at Chef Mickeys at the Contemporary Hotel- now that was worth it!)
Do you plan to do just things at the Nick Hotel or are you planning a day or so at WDW, Sea World, etc.?
If I were to go again and were just doing Nick Hotel stuff, I would stay two nights (making sure I arrive early on the first day and leave late on the last). Three nights might be enough unless you are planning to do a day at the parks or at least getting off property for awhile.
For me, the next time I go, I would request a room in building 6 or 7- those are near the Lagoon pool and the Mall. Building 6 is near the laundry room (on the 5th floor). Building 7 is the closest of those two to the free shuttle. Buildings 1 & 8 are the closest of all to the shuttle.
Buildings 1-5 are near the small pool. Buildings 6-14 are near the Lagoon pool.