The problem is that with resale stick built is worth more than manufactured and if you live in a reasonably sized city the market has determined the highest and best use for lots that will meet your criteria is for someone to stick build a house and sell it at market value, and the lots are priced as such.

Some people may say 50% is too much equity but you can determine percentage.

Even when we were mapping out our remodel, we ran the numbers to determine what the possible value could be for the home and kept our budget well under to ensure that we would retain a fair amount of equity even after the remodel Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

When he actually went to order in the pandemic, that $40k quote rose 50% to $60k.I would go through your plans and determine what you need/want, then start shopping around. 

What metrics does one look at to determine if a property is a deal?

Of course, you need to have the correct insurance for your situation.Again, consult with some qualified professionals to determine what works best for you. 

Go talk to realtors, analyze 100 deals off the MLS,talk to PMs about maintenance costs you can definitely get upto speed quickly and find a decent deal if your determined.

To determine magnitude of risk you also need to see how was the borrower qualified for the loan, did they put a down payment, is the loan greater than the value of the property, do they use a 3rd party servicer or who services the note.

Just determination.

I have 5 years of home improvement construction experience, so determining whether to write an address down came naturally to me.