[Smallblock454]

Sounds like the alarm system is still active, so the car won't start.

993 have also the alarm module on the floor below the seats. So water is a possible option.

Key fobs can be checked, but i doubt that a normal workshop can do that, because you'll need a spectrum analyzer and you'll need how to decode the signal and you need to know what you are doing.

Passenger door latch. I don't think that is the problem, because the door locks are operated separately. So if you remove the door lock connector on the passenger side the drivers side should be still operable.

It's more possible that there is a ignition lock problem and that the key fobs don't send a proper signal or that the alarm module has a problem.

Maybe check for a different workshop that is specialized in 993 electronics.