Can water landing be simulated?
Technically yes, but I do not know of any simulator which includes this. The water forces can be calculated in the same way as the air forces, so I see no reason why it should't be possible.

Historically, model tests were made to check that a new airplane would behave well when landing on water. The simplest tests would use a catapult and launch the aircraft model into a lake, and more thorough tests use water tanks where the airplane model is pulled along the water surface while being suspended on a rig. This allows to measure forces, while the catapult launch will only show the dynamics of a water landing. Results like these could be used to calibrate the computer model, so you can be sure it behaves like the real thing.