Could of things come to mind.
With low oil pressure, rattling, and codes P0012 (Bank 1 over-retarded) and P0022 (Bank 2 over-retarded) after you replaced the water pump, it may be caused if the pump had failed and caused l coolant to leak into the oil. If so, this created a "milky" sludge that clogged the VVT solenoids.
As to the rattling sound, if you reused hydraulic timing chain tensioner abd failed to bled it properly, it probably can't maintain pressure which causes the chain to slap against the guides.