After some more rummaging around in SecureSocial code I got a better understanding of how it operates.
You can use any of the providers you listed in the play.plugins file seperatly to authenthicate the user's info from your own login/auth code. just make sure you send the right parameters that the provider needs.
I liked the way SecureSocial's ProviderController class dynamically decided what provider to use, based on a parameter. But I didn't like the responses it made - redirect.. I wanted to respond to an ajax request with some data and let the client side js handle it.
This is my solution:
pretty much copy all of ProviderController code to my own Auth.scala file (a Controller). Changed the redirects related to "case ex, case _", kept the redirect on successful auth as it adds the SecureSocial session key related to the user. Removed all the SecureSocial related routes from my routes file. Put an additional hidden field with the logintype (userpass/google/fb/etc...) and configured my login ajax post to sent this along with the post to my Auth controller.
If you need more info comment here and I'll edit the answer.