Smart and ambitious move, sweat, blood, and tears. 

A reverse osmosis system (for your drinking water taps only) will take care of the sodium, it's not a huge concern unless you have high blood pressure or on a salt restricted diet.

And thank you @Joe Scaparra for lowering my blood pressure. :) I did get a really great inspector, who has followed up with me a lot and we talk pretty candidly about some of the things mentioned.

Are they related by blood/marriage?

I'm a contractor so it's in my blood.

Sounds like you're trying to get blood from a stone.

The only thing I would say is to watch rental laws and taxes since, as you know, in California it takes God and 6 unbiased judges as well as a writ signed in blood in order to evict someone.

However, in order to get the benefit of the low down payment, the non-occupant coborrower must be a blood relative.

Be careful because sharks smell blood from very far away.

I'd move on, you can't get blood from a rock.