You load your world. You can choose either offline or online when loading your world. In either mode, I'm 99.9% sure that you just invite your friends. Boom, you have a server. In online worlds though, people can drop in and drop out as much as they like.
This has been talked about and can be seen in numerous videos all over the web.
We don't know. I'm pretty sure it hasn't be said yet.
Wait till May 9th when it comes out, and try it.
This has been talked about and can be seen in numerous videos all over the web.