Yes, there is a Light of Andorra Wiki. Fixer set it up and maintains most of it. Fightmaster maintains the library. And we all contribute bits.
BUT
Things are supposed to be up to date here, and it is my fault that they are not. I have quite the project ahead of me 
I have started on the basic covenant info, and I got hung up on residents and expenses. Library comes after that. I will make a place holder and move on with the update.
As for your questions:
If you want a low/medium powered familiar, we can just hand wave it. If you want a more powerful familiar, that requires a story.
Botch dice depend on various circumstances; stress, danger, risk, mastery or lack thereof, etcetera.
To jump in, jusp post your introduction in the sandbox thread (Chapter IV, 1234-1240). You pop through the Mercere Portal from Harco when it opens in Fall 1234.