Compression test should be done with plugs removed, throttle wide open and then cranked via the diagnostic socket so that no power goes to any other circuit, just the starter motor. The vanos should be left undisturbed/no power to it.
Seeing it is on a stand with manifolds and cams removed (so valves should all be closed), a quick way to check if you have bent valves will be to put some paraffin/diesel into each cylinder, replace the spark plugs and then invert the engine. if the valve/s are bent, the liquid will escape rapidly. Dont forget to drain the oil first. Alternatively you can use a leak tester. If this shows bent valves, then off with its head...
However, from your description, I suspect something has gone wrong with the chain/tensioner causing it to lock the crank from turning in either direction. (top end failure will normally not lock the motor solid in either direction unless it is a catastrophic failure, your work on it should not have this result). I would firstly remove the sump and have a look from the bottom. See if the chain is hooked up somehow. (It should be loose as the cams are out).
Let me know what you find.