Like @Chris Mason mentions, her best friend might know exactly what she wants (hint) and help steer you clear of making the wrong purchase.

It's hardly rare as two on a lot (single parcel) is fairly common in certain areas, especially LA county.LA county is big AND diverse, since you don't even hint at the community or zip code or if this is a big house with a granny flat, pretty hard to guide you. 

Any hints would be greatly appreciated!

Do you have any helpful hints for finding off market deals at a wholesale price?

That is, did her application give any hint that she was trouble?

Contractors are busy enough right now that you may have trouble getting one out to a property that you don’t already have under contract / pending, but like you hinted at you paying them a bit up front for their time and expertise on the estimate would go a long way. 

A good realtor can let you know, but calling the buyers directly I think is the best.One last hint, learn to create a good professional scope of work.

My boyfriend had hinted at how much know-how I had to learn before I could even be remotely successful, and haven taken some time to browse through the blogs, posts, forum on BiggerPockets i now know that there's a MOUNTAIN of knowledge I need to absorb.

Then if they havent hinted to them thinking about selling say " oh by the way your house would be perfect, would you consider selling in the near future or give me the right of first refusal?"

Hint: don't use the term "sub-prime" in your business name or prospectus!