PF Accounts after I become a foreign citizen

PF Accounts after I become a foreign citizen

I worked in India for 18 years and during this time I have made PF contribution to my EPF accounts. Two PF accounts exist in my name today as my last company in India created a new UAN despite I having an old UAN. 
Since 2018, I have been working in Canada. I have recently acquired Canadian citizenship and surrendered Indian passport. I am in the process of getting OCI card.

If I come back to India and start working for an Indian employer
  1. Does my Indian employer have to create a new account/UAN with EPFO office? Or can I start contributing to an old PF account by changing my status as International Worker?

  2. What will be my PF contribution if my salary includes Basic, HRA, Flexible Benefits & Bonus? Will it be 12% of Basic or 12% of entire monthly pay?

  3. What happens to my old PF accounts if my employer creates a new PF account/UAN as International worker? Do I have to withdraw from old accounts? or can I continue to hold them with interest credited annually?
Highly appreciate if you can provide details.

Thank you,
- Srikanth