If they just rolled-bak their release, you would be back at what they released in August. And there was no September SPL in August yet, that cannot be included. Just watch that thread, I’m sure they will re-release it soon.
Not as “hard” as in the web installer. Via manual installer you can brick you phone if you try to.
There’s a nice manual here in this forum 
on how to install, also explaining how to check before possibly bricking: A safe guide to install /e/OS on your Fairphone