The mortgage payment is $1,000 on each house, so you earn $500 per house or $2,000 monthly.

Have never missed a payment to investors.

Quote from @Theresa Harris: For late payments, how late are they? 

Given that the property was worth $390K in its current condition, I saw an opportunity to make the numbers work while keeping my upfront costs low.Instead of increasing my cash offer, I negotiated a $25K down payment with the seller carrying the balance for two years through owner financing.

This will affect things like required down payment, rates, and even which lending institutions would be willing to finance. i encourage you to look up warrantability for financing just so that you don't have surprisses when your 20% down buyer cannot finance that way.

Since I'm a new immigrant with no credit score, a DSCR with 30-35% down payment is my only option, so the 50K need to include that down payment alongside all other costs (closing, rehab, etc). 

Really expedites the time it takes to reach FI when you can completely eliminate your housing payment and get into multis for such little down and start building equity/cash flow with each one.

Their insurance has asked me to return the month's payment for the remaining days of their rental (Unfortunately, I did not have a cancellation agreement).I am unsure how to handle this situation, especially since I couldn't fill the majority of the rental dates and had to offer discounts for the days I did manage to book.

Seller was behind on pay HOA payments and in risk for losing the property.

Still use paper method for mileage logs.Tried QuickBooks several years ago but it was more complicated and I did not need the bells and whistles.