Multiple Applications using single Identity Server #1801

We are facing issue in establishing multiple applications setup with ABP Module Template.

1)How to Authenticate Multiple ABP.io Commercial Applications (Main App [with Auth], App1[Auth Redirec to Main App], App2 [Auth Redirec to Main App]..) with single Main Application and return to Original Application via Angular UI
2) While generating App 2 using Application Template , it is additionally generating the User,Permission tables as well in the App 2 which actually has to be maintained in the Main Application. How to avoid this getting generated,Pls refer screen shot.
3) Also How to verify the User Permissions in the App 2 which is authenticated from the Main Application.