Game Dev - User Registration & DB management (advice needed)

When you use Discourse as the identity provider as Richard suggested, Discourse will handle email validation for you.

When the user goes through the SSO flow on Discourse and then back to your website, you can use the response that Discourse adds as an embedded query string to the sso param, containing email, username, name, groups, etc (but not password, that would not be a good idea), which you can extract and properly validate using the provided sig.