On houses below $200k, the 70% rule gives you too low of a profit - you need to lower it the lower you go (ie a $100k ARV would probably be a 60% rule).

DSCR or Fannie/Freddie loans can go up to 75% on single family homes, multi family homes (2-4 unit) max at 70% if you stick with Fannie/Freddie.Other things to consider would be:Paying points for a lower rate vs higher rate with no pointsIf going DSCR - Prepayment penalty term (0-5 years)The lower the loan size ($200-250k and lower), you should consider paying up to 2 points and doing a 5 year prepayment penalty if going DSCR.

The HUD guidelines suggest a certain rent amount, but after inspections, the figure came back significantly lower than expected.Additionally, do you have any general tips for working within the bureaucracy of the Section 8 program?

Again you can buy more properties in lower asset class area, but it's less efficient.There are many threads about appreciation, so i won't repeat it here, but my guidance to you is to think through the difference between appreciation and inflation. 

it will be a corporate/wellness retreat/short term rental destinationI need land that is close to the Action, but not too close, and preferably comes with two single family doors already built, so I can take advantage of Fannie Mae owner occupied loan and develop the rest of the land on my own and with private funding.Is Columbus a good market for this strategy?

If you're closing in an LLC/entity, there will be some requirements there as well.

This amounts to lost opportunity because if you had purchased RE, at the closing it can start producing return. 5) ADUs detract from the existing structure whether this is privacy, a garage, or just yard space. 6) this is related to number 1, but there are many more buyers looking to purchase homes for their family than there are RE investors looking to purchase small unit count properties.

Then your sale will be for $450K ish (you do subtract closing costs). 

Account for all costs, including closing fees, holding costs, and repairs.

I have focused my research on house hacking due to the lower upfront capital requirements with an FHA loan.