Challenging question! May need one of the Anaplan Integration Pros to answer. Only two ways to authenticate with Anaplan at the moment. Doesn't matter if you use AnaplanConnect, 3rd Party Extension, a programming language like Python, or through one of the extensions. Basic Authentication and CA Certificates.
Some of the OAuth methodology is available, like the certificates and tokens. Here's are two important links:
Thanks for your questions. Concerning Integrations per se, there is on near-term solution in sight for Oauth authentication. We are analyzing a future implementation but nothing's definitive yet. As @JaredDolich mentionned above, there are 2 ways to authenticate yourself when it comes to API: CA Certificates and Basic Auth, in order to get the token from the auth API server.