As you mentioned, I first require GROSS household income to be at least 3x the rent.

Unlike a standard lease where you vet one household, you’re screening multiple individuals who will be living together, often as strangers.

One time upon departing a tenant left 22 missing or burned out light bulbs in a 3 br house. 

If three adults in the household sign the lease and one of them files for bankruptcy, would that allow them to avoid paying rent for three to five months?

I checked the furnace and it appeared that the gas was flowing but the igniter did not light.

You can also make your place more trouble-free by fixing things up front that are most likely to break (new light fixtures, light bulbs, door locks, etc.).

I am open to light rehab (just not a total fixer-upper).

One broke down and lost wifi permanently but otherwise they work great.We use Kasa switches for porch lights, some interior lights and string lights.  

Quote from @Anshuman Thakur: Can someone please shed some light on how- convert 401k to SD IRA- how to use SDIRA to buy properties- how much down payment is typically required if we are using SDiRA to only fund downpayment on a multifamily CRE, and which banks typically work with SDIRAs- how does LLC structure- property management and cash flow work in this situation?

The interior was made up of high efficiency HVAC systems, contemporary lighting, and electric water heaters.