Did you try downloading the updates in iTunes on your computer and them sync them to the iPad? You may just have an available download in iTunes that is preventing the apps from downloading on the iPad. You could launch iTunes on your computer and go to Store>Check for Available Downloads.
Sometimes - signing out of the account on the iPad, restarting the iPad and then signing back in to your account will restart the "waiting" updates. Settings>Store>Apple ID - sign out, restart the iPad and then sign in again. Settings>Store>Sign in.