I don't personally think you need a formal mentor, I would recommend simply asking questions constantly to anyone in the industry you encounter, and with time you will formulate an appropriate plan and goals for yourself.

Every week, the King County, Washington sheriff's office posts a list of judicial foreclosure auctions from that Friday morning, with the starting bid and final selling price for each home. 

I don't have a formal business set up yet or an LLC.... just operating as a sole prop. 

Even if the change in ownership is merely a formality and effectively I'm still the only owner? 

What legal considerations should I keep in mind when formalizing their role in the deal-making process?

They still have to be evicted formally.

It's not likely to get better from here with this lender.You can make a formal complaint against the lender using this link: https://www.consumerfinance.go...

You can give formal notice in writing to  visit the home and get the paint and drywall if she's being uncooperative.  

It doesn't have to be through a formal mentorship program, but it is always a good idea to have a mentor and surround yourself with investors who are more successful.  

About 2 years into lending I had so many investors I needed to formalize the business and formed my first “fund”, whereby the investor were limited partners in a portfolio of hard money mortgage loans.