How do I set a facebook pixel event to track registration completion when my registration form completion redirects to my index page not to a registration success page?
Should I use a standard event or a custom event to achieve this, or, do I have to create an intermediate page that the registration form directs to and then redirects to index page?
Fire the Facebook Pixel event when the user clicks on the form submit with 'click' event listener. Standard versus Custom events is a separate issue, but I suggest sticking with Standard events where you can.
https://developers.facebook.com/docs/facebook-pixel/advanced/