A solar company recently installed a 30 acre project just a few miles away on the same power line that apparently pays the owner 45k/yr.

@Mark VesuA written agreement among co-owners is always a good idea. 

OR you could sell them with owner financing.

What's the ideal business structure in Texas for sole-owner, flipping business that offers anonymity, tax efficiency and asset protection?

In Metro Detroit there's a shortage of S8 rentals because:---Many owners are NOT willing to deal with the program paperwork headaches & tenants (why do you think many pro-tenant factions want to make it illegal for landlords to discriminate about source of income/S8?)

Probably due to all the losses they've been experiencing with all the wildfires, floods, etc. of late.We even have a case right now that required the owner to sue their own insurance company, because the insurance company denied their claim on an alleged technicality.

I just viewed what looked to be a beautiful 3 unit in the photos a few days ago, but when I got there it was apparent the building had a natural gas smell in the basement, plus the owner pays all heat for the building since there is only one furnace.

@Logan Guerrero one of the challenges with maintenance is owners not having funds.So, we've learned to prioritize maintenance issues:1) Health & safety issues2) City & S8 inspection issues3) Property preservation4) Direct marketing issues (purple walls)5) Miscellaneous

If yes, do I need to reference that the Management LLC is signing on behalf of the Owner LLC or acting as agent for the Owner LLC in the signatures?

The problem you are likely running into is the Log Cabin part of it - at the end of the day, DSCR Loans are really still intended for properties that are generally usable for full-time owner-occupancy year-round living if needed - so true log cabins are pretty much outside of anyone's box.However, its definitely a grey area on what differentiates a "Log Cabin" from a "Cabin-Style" home.