Some of the repairs here may make sense to pass off onto Sister since that may not mean a monthly demand for payment but can be managed and saved up for and then deployed.  

(how solid is the economy, what is the demand, what are other properties seilling for, etc.) 

They will continue to be used so long as there are investors who purchase them and do not demand a higher standard of instrument such as a mortgage or deed of trust properly executed, recorded and maintained.  

Recording of the substitute trustee - this too is a part of the foreclosure process in many cases and is a fee passed on to the borrower.So, there is really only one fee there which is questionable and that could just be slang term being used and is most likely legit.The problem you may encounter here is that one demand was for a reinstatement and the other is simply the responsibility of the Borrower per the documents.  

In fact, it's more common than not with the turnkey providers I know of because the properties are so in demand that they go under contract long before construction/rehab is done.

I think there will be small micro-markets - like the West Side of Ukiah - that are better positioned to weather the storm; there is seemingly unwavering demand and a fixed supply.  

Your tenant pool to select from will be small and that will mean longer vacancies if you have demanding criteria for acceptable renters. 

You need to look at your market and see what is going to sell the quickest after rehab (i.e. what's in demand).

If they feel this new guy is coming in demanding top market rent to live in a so, so complex they will leave.This is all a science to it but generally property managers are doing this on a larger scale I see with hundreds of units.    

Of course there could be potential IF the supply of houses in the area is low, and demand high.