Hypothetically The house paid for in cash would rent immediately for 1500 per month.
The other 2 houses would rent for the same amount.
Before even running any numbers just looking at it would you consider one over the other. I understand there are a lot of variables without having all the numbers.
I wouldn't pay cash for 2 houses, but I would use the cash for a down payment. This lets you get a better house or in this case 2. Using hypothetical numbers, pay cash for a $150K house or use $75K to buy two $150K houses with mortgages. It depends on your price point, but a $75K house vs $150K house (using my numbers) will bring you very different tenants.
So I'd buy two houses. Yes you have more in repairs, but you have two sets of tenants paying down the mortgage and if one is vacant, the other is (hopefully) rented.