OAuth for elgg 2.x ? or other forms of authentication that can sync elgg with a chat application?

i want/need to extend the chat features on my elgg site to include video/audio chat and other text features that are not currently available in the elggChat plugin that i am currently using. it would be great to get juho's live notifier and chat plugins finished, but right now they aren't ready and so i am looking at other options. i was pointed to the open source chat project called 'rocket chat' which looks truly great and already includes a long list of features, including webrtp video/audio calling. however, i need a way to sync rocket chat to elgg's user database for authentication purposes and to grab the avatar image etc. for use in rocket chat.

rocket chat uses Oath, saml and other methods of authentication (that i know nothing about), so it may be the case that i don't need to use OAuth, but since OAuth is already coded for elgg, i thought i would look at using it first. the challenge here is that the OAuth plugin has not been updated since elgg 1.8 and i have no experience with it or with using elgg's web service / API features... so my question is:

what is the best way to allow a 3rd party app to communicate with elgg 2.1 for the purpose of using user data in a secure and private way?