The valves have not hit the pistons on anyone's zetec on here due to a broken timing belt. (Though it's never been fully proven to not be a possibility, it hasn't happened to any of us)
What is this tool from autozone you speak of?
Yeah, you need something to lock both cams, the crank pulley isn't gonna turn if both cams are locked.
Yeah, it is a good idea to replace the tensioner, as well as the idler pulleys.
