Both units are approximately 400 sqft, "yurt-style" cabins with large decks.

It came out to $823 in expenses and in the area Section 8 is paying $11400 to $1600 a unit.

If one or more units are vacant, the remaining units often don’t provide enough cash flow to cover expenses, making it harder to meet operating costs.Maintenance costs: A fourplex comes with four times the appliances, plumbing, HVAC systems, and other components to maintain, leading to significantly higher repair and maintenance expenses than single-family homes.If you want to see the detailed calculation, read this BP blog - More Units Doesn’t Mean More Money—Why a Single-Family Home Can Beat a Fourplex.Resale value: Multi-family properties have a limited buyer pool—mainly investors—who base their offers on CAP rates.

My advice is look for a good 2-4 unit investment property that my be a little outdated or need some TLC/renovations. 

In 2024 we added language prohibiting residential tenants from using portable washing machines or portable dishwashers in their units.

He took a 401(k) loan to fund the down payment on a four-unit building in a rapidly appreciating neighborhood.

Ask how many units they manage and how much experience they have.

Ask how many units they manage and how much experience they have.

Since your an estimator are the materials and labor based on facts (i.e. hard costs a labor units) or a guess.Nothing personal but I wouldn't consider anything you wrote there, if I was buying I'd do my own estimate/SOW. 

We saw huge appreciation in the 2018-2022 inflation run up, but that has significantly slowed these days in my opinion.From a rental perspective your monthly income per unit after all expenses with a typical 20% down payment is likely $100-300 when you find a property that will cash flow.