How to get a CMOS transistor SPICE model?
Usually the transistor parameters are provided to the customer by the foundry after signing an NDA (non-disclosure agreement).

Transistor modeling and parameter extraction is a nontrivial task and usually based on a large number of measurements to get reliable data for the models. Of course with an automated setup this task can be done very efficiently. Just have a look at a BSIM model file and the number of parameters there to get an impression of the required effort.

Extraction of layout data does not result in transistors models. By extraction just the transistor geometry is obtained. Existing transistor models are needed for simulation.

I think the models you found on the internet are a good starting point as they seem to be based on an existing CMOS process.