I think it's the work of a nutty fan.
I don't think so. The notary already said that they were at Calabasas overseeing Katherine's signature. What fan can go into Calabasas house with a notary and get Katherine to sign a page with her name and address on it?
This was definitely someone close to her.
Remember during HTWF case, how she gave a declaration of support and there was the dispute between her lawyers whether she signed it or not? I think whenever a family or a lawyer puts something in front of her , she signs it and not necessarily knows what she is signing. In this instance she signed a page with her name, hayvenhurst address and kids names and birth dates. I'll go with she wasn't aware of what she was signing.