Since you mentioned that your CPL has been issued you wont have the privilege of conversion anymore .
You will be treated as an Indian CPL holder who will be going abroad to get an IR rating
Hence the flow chart wont apply to you .
The second link I gave you regarding the IR endorsement abroad is what would apply to you . You will need to some FAM flights prior to undergoing any IR training and IR check .
I would suggest you take a printout of the second link , go to vashisht and ask him how many hours you have to fly and what else you have to do prior to undergoing the IR check and tell him you will be going abroad .
You will need more than 45 minutes for the IR check . Ideally 1.2 hours total time with 1 hour under the hood .
This is the DGCA form for IR check
http://dgca.nic.in/forms/crew-d/Prof_IR.pdf
And Yes IndiGo does require ME IR on your DGCA license
For more details look here
https://pilot.cae.com/Programs/Indigo.aspx