Board Thread:News and Events/@comment-26005122-20151226051208/@comment-26005122-20151229000708

You can use any Tsum you want, it's just that using the Star Wars Tsums except for Leia and C-3PO will give you bonus damage points when you use them.

If you don't destroy it within the 60 minutes, you will have to wait to try it again. Which I believe is an hour wait. And it will regain some of its health back, so it won't be at full health, but it'll be a little more than it was when the 60 minutes ran out.