@Jack McWatters You have a great deal here, but IMO I have bad news, you're going to eff this up. I'm talking from hard-knock experience, and limited info from you. I've done some crazy deals in my life that I had no business doing, and it's always based on reducing what the owner wants vs. what he needs. The most important thing for you to do is not get laughed away. Find out what he wants, and figure out how you can help him with THAT. It may be a 30 yr, but I doubt it (for several reasons). It may be a 2-5 yr with balloon. It may be lease. Or it may be a conventional loan. Nobody on BP knows that, only the seller does.
You can score this, but ONLY if you help the owner with what he needs. Who cares if you're green! You can help someone out. And if you're lucky, he may be empathetic knowing that he's helping someone out to become a homeowner in a nearly impossible SoCal housing market. Just remember this will only work if you can meet his needs, it's up to you to find out exactly what they are.
I hope you get this house. That would be friggin awesome!