Until you get your first pay slip at IndiGo as a First Officer, you know nothing.
The airline and the school can and will change the requirements. India and it's airlines are in very uncertain times, it is impossible to say if they will have any demand for you when you complete your training.
At the moment IndiGo is actually over staffed with pilots, in excess of 800 at present.
The Indian market also at present has experienced A320 First Officers available, depending on IndiGo's preference they may or may not choose these over cadets.
I would expect the airline to either significantly reduce cadet pay, or not make a cadet an employee of the airline but a contractor with a daily rate.
Worse still, you pay them to fly the aircraft.
These are all tried and tested methods, and IndiGo is a savvy airline I am sure they are well aware of what the other leading LCC's do... including the one operating over 200 A320 family aircraft.