This is in the Los Angeles area.What are the mechanics / logistics around this?

With a house that big, I would say about 100-120k would get the job done unless you need to do major mechanical updates!

These will be your "playback" mechanisms.  

I would find a local, active settlement company that works with a lot of investors and they can easily walk you though the mechanics of a seller financed deal.

I utilize Cornell Law School's public database.https://www.law.cornell.edu/uscode/text/26/4975The language is as follows, with the specific word "between" used: (my emphasis below).

Take the age of the major mechanicals and roof etc and find the cost.

I am about to finish my Bachelor's in Business with a triple emphasis in Accounting (mainly), finance, and management.

Now after the title check is this gentleman free and clear if someone later on down the line claims a stake in the title (i.e. mechanic lien of sorts)..is this were title insurance comes in? 

Some properties are turnkey where factors can determine whether your knowledge base will suffice or you need a more in-depth view others are heavy deep renovations where it would be a best investment protection to know what you don’t know; possible septic issues, roof, mechanical electric... then it’s best to get a pro if your a pro or have one. 

This, officials have said, should include a local workforce with experience in biomedicine, chemistry, computer hardware and software, electronics, materials and mechanical systems."