Is the pool available for those who are not staying in a room at the hotel? If so, what is the charge for those who just want to go to the pool? Is there an age limit?

There likely an age min, for unaccompanied children; which likley 13 yrs of age if there is no lifeguard

It is available at certain times, i think there is a $10 fee or so. You find info on the hotels website.

You can't even get on the elevator wothout a room pass, so I would assume no.