Backup Exec Infrastructure and license

Good Morning.

I can not understand what licenses I need. I try to describe the infrastructure in order to be more clear, I state that I would use infrastructure CASE.

- 1 Central Server Enterprise.
- 11 Server Backup Exec managed.
- 12 Windows Serve 2012 R2 who need an agent.
- 1 Exchange Server 2013 (I would like to install the agent database on the central server)

1. Do I need a Windows agent for the Exchange server?
2. The license Enterprise Server Option includes the agent already Database and Application, or must take it apart?
3. Each server Backup Exec agent included in Windows to himself?

Please help.

Thank You