Too many unknowns.

Do not tie it up into something illiquid or unknown just to squeak out an extra minscule return.  

If the defendants are unknown in a quiet title action, the court can allow alternate service… likely publication in a local newspaper.

But to share another perspective, I've seen anything 'of significant value' that does actually go to auction in WA - especially with a structure- of any type- go for (honestly) quite close to the mls/fair market price, and some- (when the full range of issues/challenges & unknowns about structure/condition were taken into account)- likely went for more via county auction..This is just my personal observation bookmarking, watching auctions, and doing significant title/etc research with the intent to bid/buy in some cases- across western WA (Specifically the last 3-5 years).

seems like the original owner is the missing link. if you (your attorney) can get their side of the deal, it would/could clear up a lot of the unknowns. 

But there's been times when the seller paints a picture worse than it really is, mostly out of fear of the unknown. 

Just because there is only one known heir doesn't mean there aren't other unknown heirs, (as unlikely as it may seem), creditors and taxes. 

Unknown people kill other unknown people to help  advance the victory of some other unknown persons wants and wills and it's ok because we call it war. 

Sports Illustrated, 6 Nov. 2000The narrative plot is clearly defined, and it is classically familiar: Huck (without Jim) and Tom Sawyer light out for unknown territory to discover their manhood by successfully confronting the harsh adversities of life.

For out-of-state investment, my philosophy is, if all of the unknowns in my mind are not answered, I don't go.