Hey! About n°9: I know it might sound a bit like cheating, but I found a way to delete a clan!
!WARNING!
Before starting the process below, make sure the clan you last opened is NOT the one you are trying to delete, otherwise the game will stop working unless you re-download it.
1. Open the folder with the game inside.
2. Instead of clicking "main", go to "saves".
3. Look for the text file "clanlist"; there should be all the prefixes of your clans inside.
4. Delete the name of the clan you want to erase.
5. Now look for a Exell file named "(Your clan name) + cats" (ex. Testcats) and delete it.
6. Look again for a text file named like the clan, and delete that too.
Done! If you enter the game afterwards and select switch clans, the clan you erased should be gone :D