[Quoth]

You only need a WiFi point. Most phones now can do that. It's possible also to use a laptop/PC that has WiFi and cabled ethernet to share the Internet by Wifi. Free software or included.

Kobo does zero with the email address. It doesn't even need to be real.

There is no need to bypass registration unless you are not able to access internet ever, in which case where do you get ebooks?

I've used Linux for years and don't have any ereader vendor's applications on WINE or a VM.

Maybe your WiFi has settings not compatible. I've setup five Kobos now without any applications or database hacks. Just made sure the WiFi was sensible and used a different email address. I used a specially created one years ago, the first time and it's still not had any Kobo email nor any spam at all. Only emails are my own tests.