Que- which type of data replicate in replica@tion and reverse replication process?
With proper permissions you can replicated everything from author to publish. In AEM everything is content.
Please check Replication
Using replication, you can replicate directly, however, can't replicate access of the users.
IN later versions of AEM - you cannot replicate user generated content - like comments on pages. Community has its own way to move data from Pub to Auth.