Hi,
I don't think you've quite done that right, no. For starters, each section will need a different
baseurl since each section is used for different things, so you can't use the same URL for everything. Also if you are going to be hard-coding it like this, you'll also want to comment out the
mirrorlist lines.
So for example, for the main
[fedora] section, I imagine you want something like this:
baseurl=http://ftp.heanet.ie/mirrors/fedora/archive/fedora/linux/releases/16/Everything/x86_64/os/
since that's apparently the URL that it was looking for before you made this modification, going by the other commented-out
baseurl line that's there. You'll need to similarly change the lines in the other sections to the correct appropriate URL, which you can get from looking at what was there before.
Again though, there's a bigger question here: what are you actually hoping to do ? What is the
yum command that you're ultimately hoping to run after you've done all your cleaning and listing ? Which package(s) do you need to install ?
It's also worth pointing out that you can just use that first URL I gave you (the one that directly links to the package directory) do download and install any RPMs you might require, if you can't get your Yum config working in the end.
As for whether you should use Fedora 16: well, no. Absolutely not, if you have any choice at all. It's entirely obsolete, and hasn't received any updates in almost four years, so is bound to be full of countless security holes by now. If you want to know which versions of Fedora are still actively supported and/or receiving updates, then you can check the Wikipedia page on Fedora's version history here.
Fedora version history - Wikipedia
So if you're going to be using Fedora for whatever it is you're wanting to do, you definitely want to be using a version that's still actively supported and has a fair while left in its lifecycle if you possibly can.