Unity 2017 Unet - Dedicated Server

Hello.

I would like to start with my next project in Unity. Yesterday I've successfully finished my game with Multiplayer. But it is server-client and other clients based multiplayer. Everything works well and I understand how commands, RPC and other stuff work. There is no problem.

But, I've got a new idea for next game and there is a need for dedicated server. I know that I can use NetworkManager.StartServer() and it should be my "dedicated server".

If I do that:

1. Is there any possibilty for running it in batchomde on Windows, I would like to make it a "console app"?

2. How can I send [Command] to the server if there is no player? Is there any way to inform server, for example: I've shot and take a control of my bullet. or Hey Server, I'd like to send a message to chat, take it and send to others. I hope you get, what I mean.

3. How can I send [TargetClient], [RpcClient] from dedicated server to players etc..?

4. Is there no fee for self-hosting dedicated server? I mean If I run it on my own, am I obligated to pay Unity 0.49/GB$ or my only cost is a server hosting cost in my Host Service?

5. How can I get external ip of server, in my current game I used Hamachi to connect people, but I would like that console server app to take ip of pc where it's run on its own, automatically.

6. What should I know something more, what I didn't describe here?

Thank you, Jakub