Yes You are correct , it is one way of doing the ensemble creation , yes step 5 is needed and after running it you would have three fabric servers running in an ensemble and you can manage the containers with either of server1 , server2 server3
I would recommend the following
1. Have 5 Servers
2. Installl Fuse in three of them
3. Run Fabric:create in one of the server run fabric:join in the next two
4. ensemble add the servers
5. Create the containers child ones using fabric:create-container-ssh on the rest of the two servers
The above way ensures that the fabric and zoo keeper chatter stays away from the application chatter , but your way of doing it is just as fine.