V1 vs V2?

I am an App partner, trying to offer 1)SSO and 2)call APIs to retrieve school, student, teacher, class, and enrollment data.  Ideally, we would like a district administrator to grant our app permission ONCE by accepting the consent framework, then have our App call APIs nightly.

Weeks ago (before we were aware of the School-specifc APIs), we released an App that achieves SSO.

Since there were V1 and V2 endpoints, we assumed that V2 would be around longer than V1, so we relased a multi-tenant SSO app using V2 (B2C) and OAuth 2.0   (now live - https://office365.discoveryeducation.com).

    client_id=49f34ce6-25ed-4b43-8162-6171a2eeb9e2  

My questions:

1)Is the workflow outlined above possible (offline access to API)?  If so, what permissions do we need to set?  

  I found a Word doc that may be outdated and indicated DELETATED permissions.  I suspect that we actually want APPLICATION permissions.

2)Are the school APIs compatible with V2 or do we need to build a new app that uses V1? 

    The school API documentation references Graph authentication documentation that is ambiguous.  At the top, it indicates that the Azure AD endpoints [v1.0] are needed for schools, but scroll down to the comparison chart and notice that school is included in both 1.0 and 2.0.

     https://graph.microsoft.io/en-us/docs/authorization/auth_overview

3)If both are compatible, are there any advantages to using 1.0 over 2.0? 

4)Once an external tenant accepts our consent framework, where can I go to see the EntityIDs that have accepted?   OR is the expectation that a district administrator will provide me with this value via email?