This is less risky and can earn you money quicker to use to buy investment properties.Also ask burnt out landlords if they would sell with owner financing.

Home prices can go as high as they want, but if people can't afford them, they won't sell.

Sell the property, buy cheaper, and have more cash to put into another?

Guides here; https://selling-guide.fanniemae.com/sel/b3-3.1-08/rental-inc... 

Years when there are bidding wars are good years to sell. 

Both on one loan may save you a bit up front in costs, but it'll make it more complicated if you ever decide to keep one and sell one.

After buying this house, I partnered with others to invest in a duplex in the Wichita area.At the moment, I’m living in Tennessee, and I’m weighing two options: either selling my house and using the proceeds to buy a duplex in Overland Park or Wichita with my partners, or keeping the house for another 3 years, transferring it to our LLC, and renting out the entire property to maximize its rental potential ( $1400-$1600 ) I currently owe $200k on the property with a 6.5% interest rate, and my monthly payment is between ($1,700-$1800).

Or they've dealt with one of the 50% of realtors that sells 1 house or less per year.

If you do not have those it will extremely hard to ever sell it to someone who will require bank/lender financing or refinance it down the road if you want to pull out cash on the ARV or future equity.The other rule of thumb is that you buy it New and that it was never on another property or location, simple built onsite or trailered in from warehouse. 

It's arguably the #1 most important factor to a listing, be it for leasing or selling.