(heloc or refi)I am an engineer by trade, and own my own comapny (AHAE Designs Inc).

You'd have to engage a grading contractor who might be able to give you a ballpark estimate, but it would maybe have to be engineered with rough and precise grading plans to determine costs. 

My main goal is to identify an opportunity that can be scaled from a couple of spots to a dozen, to several dozen eventually without the need to completely re-design or re-engineer the layout without respect to providing utilities. 

One of the BP workers stated they were working on search engines to facilitate posters questions based on the BP database.  

True, I never built anything more than a treehouse when I was eleven, but technically a treehouse is a house so…All I had to do was work with Honomobo to finalize the design, get architectural drawings, receive HOA approval, get a county building permit, get a driveway permit, clear trees for a build site, find a logging truck to take those trees to a lumber mill, find a mill, find someone to take the lumber from the mill to my house, dry the lumber, take a semester of woodworking to learn how to make furniture, engineer/permit/build a septic system, get a well permitted and drilled, install a well pump, learn what a pitless is, install a water line from the pump to the foundation, install a pressure tank, connect the house plumbing to the septic and pressure tank, get the the power company to permit and install a podium for power on site, run power to the foundation, connect the power to the house, engineer a foundation, excavate, get two different sized steel wet plates fabricated, pour said foundation with wet plates mounted all at the same elevation in twenty-five precise locations, hire a crane, hire rigger, hire a welder, build a retaining wall because the dropoff from house to ground level was higher than expected, insulate the crawl space on my own by watching a YouTube video to learn how to load .22 caliber cartridges into a ramstead gun and shoot two and a half inch nails through insulation board into my foundation, badger a supply company until they finally delivered the right insulation board, get them to take away the wrong insulation board they brought that was broken by the wind and scattered into pieces all over the property, find an illusive 3x3 foot crawlspace door, learn how to use a core drill to make a four and a half inch hole in my foundation to install a code required fan to vent the crawlspace that my engineer thought was a stupid requirement and failed to tell me about, figure out what the hell going on when the Honomobo project manager tells me the measurements you gave him of the now poured foundation are wrong, have a panic attack, review plans with engineer, realized the project manager was mistaken, scream into the void, get the last available short term rental license application that had a thirty-day expiration window to pass all inspections, coordinate all subcontractors needed on install day, check with the sheriff about parking semi-trucks on the road, rent a porta potty, rent a dumpster, have coffee and donuts for everyone, oversee the Honomobo install crew that didn’t need overseeing, pass a blower test, pass state inspection, pass septic inspection, build a wooden curb to cover protruding rebar for an unpoured patio, build a temporary front door landing that could theoretically be be permanent so as to pass final county inspection, get a certificate of occupancy, pass the county short term rental inspection on the very last day before it expired to get the very last available license so that I could rent the house to make money in order to no have immediately have to sell, pour the sidewalk and patio.

Now he says he needs to hire an engineer.

I'm working with a local engineer on finalizing a couple of ready to build ADU/triplex plans that I designed specifically for Oregon for my own uses, but you've got me thinking re: scale in general.  

My borrower also had to document that he has no knowledge of farming and no intention of farming and that was easy because he was engineer with a good paying job. 

Foundation/structural engineer determined a water downspout on one side of the house caused the soil erosion. 

As for Market knowledge where would you recommend using as a search engine?