Though I rarely see duplexes or multis come up in auction.  

Yea it's about a block away from northboro elementary. 33407 is the zip code about two or more blocks east it's a spotty area but the block that it's on and east from it has a combination of 400k+ houses and multifamily properties.

In northern California you rarely need an attorney to buy a primary residence.

Assuming I put in the hundreds of hours required to master this niche, what are my odds of seeing 15%, 20%, or even 30% annual returns in, say, NPN 1sts or NPN 1sts in combination with performing?  

It is rare when I dont answer my phone.

We saw a listing for a 'rare' SFH brownstone that just hit the MLS at 900K, with a backyard and parking. 

But that is based on the assumption that you truly have to do no repairs and those deals are very rare in the sub $100K price range.

This is one way to combine a low-cost marketing tool with your desire to get out there and make this happen. 

Yes, but they are rare.  

I guess this would be considering a wrap around mortgage since I'd try to keep paying on my mortgage - though I do have the ability to cover if they were to activate that rare due on sale clause.So my questions are for anyone who has had experience in structuring seller financing deals:1) My initial thought would be to structure it to parallel my own ARM to keep her payments low for 5 years (close to what she's been doing for rent) and have a balloon payment in 2020.2) What kind of interest rates are usually charged in this situation?