If you are testing your Webhooks integration rules or OptimizeFlow webhooks and find that first name/last name are not passed through (or your email is shown instead) this is because you MUST test when LOGGED OUT of your WordPress site and use a different email address than the admin email.
Anytime you test anything on the frontend of your site, including checkout forms, it is best to test on a different browser or incognito window. Or just make sure you are logged out of the WordPress Admin. This is important as the frontend of your site might be cached so you'll want to make sure the test goes smooth while the cache is running. In most cases, admin users are not cached. Also make sure you are not using any email addresses that already exist as a user on your site if you want to test the process of adding a user to a membership integration.