The OAuth providers bundled with TIB are pretty specific, you would probably need to fork and clone the github OAuth handler (it's very generic) to get the callback URLs set properly, so out of the box, no it won;t work. [There's a generic OAuth handler branch in development] at the moment, but it isn't hooked up yet.
It looks like you are getting the error because the dashboard credentials are incorrect in your profile configuration. you will need to ensure the Dashboard Credentials are a valid Tyk Dashboard user
Yes, TIB will generate a user object from the google info and then embed that data into the token
meta_data of the token so you can inject it into the header, or look it up with the API later.