Assuming we’re talking about California residents and California property, and there is no net equity in the home, the answers are pretty clear.
A. No
B. No, wife does not owe husband anything. If the only loan is the purchase money mortgage, the property itself is the only security for the loan.
C. No
If there is positive equity in the house, the husband is entitled to get the first $100K back first if he can trace the down payment from a separate account.
