First of all, sorry if this topic sounds harsh.
Unfortunately, arkenfox user.js maintains a lot of automatic connections, geolocation, safebrowsing and son on.
You old guide was by far better than this.
Nowadaways, Mozilla is bloating its browser and it's almost impossible to mitigate it.
After trying dozens of user.js this is the best I found (from a forked arkenfox one)
However, we still have to add firefox.settings.services.mozilla.com to our host file.
This way, it seems there is no unsolicited connections, but what will be the next step? Will we have to continue adding more and more in the future in order to control Firefox?
To sum up I think you would consider even deleting that guide.
Thanks for your time.