Great! Good to hear it. Consider marking the response that helped as 'useful' ... helps me 'earn' my badges! ;)
Also ... be forewarned ... when you upgrade to 3.3/3.4 there will be issues with the 3rd party plugin you are using and the core code which includes config of Oauth2 services ... Google is one.
Advise getting a look at your mdl_user table now to see how users that authenticate with your addon now. That info will be useful when planning/doing a conversion of authentication of existing users in your system such that those users do NOT need to be removed nor do those users need to create a new account ... ie, their row in mdl_user keeps the same ID number (which means any work submitted, quiz taken, certs acquired, etc.) won't be orphaned or lost.
'spirit of sharing', Ken