I took this cruise last August. Awesome.
It can be exhausting however with so much to see & do. If your teens go on excursions there is really little time to be bored.
I have posted a review here that you can refer to on tours.
You did not mention when you are going ?
But, we did have some warm days & people were swimming. Plus there is the indoor pool they can use if it is cooler. And the hot tubs you mentioned.
Hope you enjoy it.
PS here's a link to my webshots albums. I have several albums from this cruise you can check out.