1) No, i suggest you to buy a domain from offshore registrar.
2) Look for i7 processor and at least 16GB RAM, they have these auction servers for arround $21-$25 all the time
3) ???
4) You have to install Linux system, after Linux is installed, boot server in Rescue mode, install Windows 10 and restart - then login via Remote Desktop Protocol (RDP)
5) You must publish a stream via RTPM (at least that's what im doing). If you're planning to directly use Hetzner server to deliver content to everyone else, then Hetzner wont be a good option. But if you have 3rd party provider such as WhoStreams or Youtube, then just open OBS and put in RTMP details and start streaming, no GPU required, just CPU