Best way to perform SQL Server replication over multiple servers?
I had a long answer written on stackoverflow, but then you deleted the question about the same time I was ready to post it. I am not going to put the same effort in again, but in short:


Check out the stairway to replication: http://www.sqlservercentral.com/stairway/72401/ 
It does not cover bidirectional transactional replication, but it covers the permissions involved in setting up transactional replication. That should allow you to figure out the bidirectional setup as well.
You might want to check out merge replication instead. It was designed for multi-node bidirectional synchronization of data and offers nice conflict resolution handling. However it adds a guid column to each table.