Q: Multiople Misfire at almost all cylinders all at once no warning with codes

If you have a multiple misfire, the camshaft tensioners would not be the first place I would look for trouble. I would first check for air leaks and then carefully check the fuel and ignition systems. Camshaft tensioners usually manifest themselves with oil leaks and rattling noises before they get so bad that they cause misfires. In answer to your questions, a cam tensioner on one bank will not cause misfires on the other bank, and you will not be able to detect cam tensioner problems with a compression gauge. However, a technician who is good at interpreting a vacuum gauge may be able to pick it up. If you contact Your Mechanic, they can send a technician to your home to check out and diagnose your car so you can decide what to do.