A clueless ADULT seller with all his cognitive abilities INTACT also made certain choices that were most pleasant to him at the moment and now pays the due price by being stupid.

It appraises for $250k so the investor (after all you can’t sell to an owner occupant, the buyer who would pay more than the investor.) has to bring 20-25% of the $250k plus all of the $50k extra.

I would sell.While I like the idea of helping out another service member, I'm not sure the math will work for the buyer. 

My friend came to me.... and I tried to get her the most I could based on what end buyer's were willing to pay How did you finance this deal?

I just had a buyer that I was representing put a FSBO under contract.

However, let's say the lender were to foreclose on an existing PadSplit, what has a larger buyer pool: (since any lender that want's to foreclose wants to make the disposition of property as seamless as possible), a standard SFR, or an SFR with multiple modified bedrooms/faux walls?

Deals with approved ADU plans are especially attractive because they offer a higher return and flexibility for future buyers, making it a prime investment opportunity.

Most firms in my market charge a transaction fee against the buyer agent's commission.

They do hundreds of transactions a month and can guide you better than most attorneys when it comes to title issues.They use a complicated form that creates extra work and confusion with no benefit to the buyer or the seller. 

Buyers always anchor to the last price they paid, and the market has moved 20-25% since then.