Pi Zero has no networking iirc
Noobs can't use wireless
It uses the 3B's on-board wifi fine, in the NOOBS menu there's an option for connecting to a wireless network and then after a moment it shows all of the downloadable OSes.
Hold shift down when you first power on to enter Noobs, you'll need wired LAN to download options as Noobs can't use wireless and yes going straight to Raspbian is normal (make sure you update it as normally it's horribly out of date)
Not on all of the Noobs being distributed via SD with the official starter kits, quite a few of the images dumped on the SD cards are hideously out of date.
If I was to install a different OS using NOOBS, can I hit shift again and install a different one? Or will installing a new OS mess up the NOOBS menu?
Yes you should be able to. Its very good once setup.I use my Pi 2 for OpenELEC only but interested in pi-hole now that I've seen it. If I installed pi-hole onto raspbian would it still work even if I didn't boot into it? I'm assuming I'd need to set up dual boot using NOOBS?
LibreELEC is much better than OpenELEC btw.
OpenELEC is as good as dead.
edit, that Pi-Hole looks neat!
Also do people use each Pi for one specific purpose or can they be setup to handle multiple things?