Twitch integration + Opencart custom fields

Vera_Yatsula

Hello, I just created my Opencart install and OneAll Social Login extension integration today, but I have some questions/potential issues that might arise in the future. I just want to make sure it's all good before continuing the project....

I see when signing in with Twitch this is the basic data that is retrieved during API connection:
Formatted Name
Email Address (Verified)
Preferred Username
Profile URL
Profile Picture

The email address already gets linked to Opencart's email field.
How do I link the Twitch 'Preferred Username' to a new custom field in Opencart (ex: Twitch Username)?

Also, if a Twitch user updates their email address on Twitch then tries to login on my site using the login social login, would it try to create a new account for them because the email address on Twitch is now different than what was originally used to create the Opencart account?