Hire an attorney asap. Walking away is never, ever a good idea.
RE your own house: you definitely need an attorney for this one. Generally, it depends on who owns what. For example, your own residence might be owned by you personally, and the other properties as LLCs or some other entity.
These are all questions you should be discussing with the company you pay your monthly payments to. You have options other than walking away. Call them ASAP.