As such, this has allowed us to do several BRRRRs without any financial hurdles at the end. 

Every waterfall model I've ever done has used IRR targets as hurdle rates. 

but I don't really want to risk going through a tough escrow with a novice buyer trying to shave me down with contingencies and unreasonable demands related to inspections... especially in a softening buyer's market.

Especially as some sellers have unreasonable expectations.

I think narrowing down your market is going to be your first hurdle.

No, of course not, but we have some hurdles and barriers in place to try to mitigate such things. 

After all, unreasonable people tend to be unreasonable. :)

Some loans will come with defeasance or yield maintenance, while others will have step down prepayment penalties.A good loan broker who specialized in MHP debt can guide you with respect to the right choice for you as the buyer, which type of lender will be best suited for the park, where the terms will be the most favorable, and where the hurdles will likely be.

There are a ton of empty lots across Detroit, which seem in theory like "easy" places to pop up a pre-fab SFH or small multi.I did some preliminary research here and via Google and see that most people's experiences seem pretty positive with key draws being the cost = less than or equal to standard construction, materials being eco-friendly and sturdy, shorter construction time, similar appraisal value, to name a few.My questions:Can anyone share any experiences specific to Detroit or the surrounding area with regards to permitting or legal pitfalls to avoid or hurdles to jump over?

For passive investors we typically include a preferred return 6-8% and IRR hurdles based on investor return.