Hey @joebuhlig - welcome to the Auth0 Community!
- Rules can post to an external datasource, but bear in mind that the success of your authentication flow will be dependant on the response of the datasource. If for some reason the responses of the external datasource are delayed, or the external datasource does not emit a response back, the whole authentication flow would fail, unless you catch those specific errors, but then you could end up out of sync.
- It is feasible, but it all depends on how your application is set up. The ID Token can be enriched so that the
/userinfoendpoint shows that information, and then you could leverage it in your application. Again, that would depend on how you set up the application, rather than Auth0.
Let me know if this helps!