Well, that scenario is what I thought you wanted to do in the first place. Thus the X server (!) used in the xinit command in the OP - it's a pure VNC<->X server. Xvnc is *not* x11vnc. The latter provides a *running* X server display via VNC. The further however is an X server on its own, as well as being a VNC server. Thus the start-up on another port.
Just install (e.g.) tightvnc, it will provide the Xvnc binary.
As for the list of questions:
1. has nothing to do with all this. Look this up for the default raspi X server, whatever that might be.
2. Xvnc is what you're searching for, I think.
3. You want to automate the start of Xvnc. Just use that xinit line suggested in the OP in your system startup scripts, e.g. /etc/rc.local on Arch Linux.
4. Hm, I think it should adapt to the orientation the framebuffer currently has, but that's it.
5. Via launchpad: shift-V-Q. Or adapt the config.lua file, a function for quitting is provided, you can call it for a certain key combinations. Would require messing with Lua, though.