PATS is Passive Anti Theft System. System is a security feature comes with the Ford cars. It is similar to the iCAT system which comes with other brands. The system works as, when any body tries to steel your vehicle by a wrong key, the system grant acces to the thief to start the ignition. But the vehicle stops after 10-15 meter by blocking the fuel supply. This system helps to save your car and the thief might be captured also.
Ford Classic is a good car and even if the car is discontinued Ford will keep its parts for at least the next decade. In comparison to Etios it may be an old car but it can easily match Etios performance and comfort. Though, if you are planning to buy any one of these we will suggest you to wait until Ford launches its next car, the Figo Aspire. Know more about Ford Aspire: http://www.cardekho.com/carmodels/Ford/Ford_Figo_Aspire
The has been no such announcements from Ford motors on this. So the model is not being phased out in near future. But, yes eventually the model would certainly be phased out, but when is that going to happen is not certain.
No matter a car discontinue or not, the manufacturer makes the parts available for a good 8-10 years after it is being discontinued and as manufacturer uses the same engine in multiple models, there is a higher probability that you can get engine parts easily.