mechanic replaced timing belt. then said overnight the fuel pressure regulator leaked putting too much fuel in the cylinders. This created too much pressure when trying to start the next morning...

if there was cement, even, in the cylinders, the pistons would not move, the crank would not turn, and the timing belt, running off the crank gear, would not move- meaning that it would be impossible to turn the cam gears- in other words, this is the opposite of the situation which bends valves: the bottom turns but the top doesn't- and, if the "fuel pressure regulator" was bad, wouldn't you have noticed it before it went in the shop? Who is this guy? Does he seem professional or is he out under a tree- did you have the belt changed as part of regular maintenance? Did you try to save money by going to him? If the guy bent the valves because he put the belt on wrong, he should pay to fix it- don't fall for that lame story- "causing the timing belt to slip" a brand new belt, adjusted properly, is not gonna slip- good lawd people who don't know what they are doing should not be trying to change cam belts- even if this story were true (in some parallel universe) he should make it good anyway- it is not your fault- you should not have to pay for it- and it WILL be expensive- this guy knows that- but he can do it for you with less expense to him than if you have to pay for it, straight up- he sounds lazy and self-serving- what a mess-

The fuel pressure regulator on most engines is on the out side of the engine. So if it does leak fuel it will not leak into the cylinders causing the lock up problem. Sounds like the cam/crank was not lined up correct & engine was cranked causing the bent valves.