It's essential to get all the information you can about the squatter: did they ever have a contract with the owner, how long have they been there, how many are there, has anyone told authorities, do they have access to any utilities you'll have to pay for, etc.

@Teri Lurie, any excess funds can be claimed by lien holders in order of priority and then to the the owners.

Does anyone has information about this Viventum development other than the one in the web?

Pottery Barn, West Elm, and Crate & Barrel are a touch above without being excessive. 

If we name someone other than our daughters as executors, that person cannot make a deal with you as the authority to sell the property passed to our daughters, the trustees, as the property is now in their hands.

It's possible that the back-fill wasn't properly graded and excess water is running along the path of least resistance underground toward your house.  

California charges a minimum tax of $800 a year per LLC, and more if you have gross receipts in excess of $250k.

Yes, you're correct about the unincorporated County area, so the County is the authority, not the City. 

My profession is software / web design and I am interested in property management and using a property management type software.

Rolan, I would agree that paying 40% seems excessive given the fact that you and your wife are taking the most risk.