[Q] Help with building a ROM from OEM source WIKO FIZZ (MT6572) topic

Beloved community. I need your help.

Scenario: The Wiko FIZZ of my GF stopped working out of the blue. Several searches online found me some threads with frustrated users.
What i think i could do: Reboot to recovery --> Wipe data --> all good. -->WASN'T!!

So i started looking for a factory image i could flash. Apparently Wiko has oneclicktools for almost all of their smartphones to get them back to factory state. Not so for the FIZZ. I came across a collection of Factory images and again, the FIZZ was missing.

So i came across this site: http://www.wikogeek.com/
They provide source code to everybody who wants to do developement with his WIKO.

My final questions to you:
1. This is only the source for the Kernel or am i wrong?
2. Can i build the kernel according to all the nice guides out here or do i have to care about something special? (recommending a specific guide?)
3. Once i got my Kernel ready. Could i take any ROM, made for MT6572-Devices and get the FIZZ running again?
4. Is there anything else i should try before messing with such stuff in order to get the FIZZ running again?

Thank you much ;)