And as I explained earlier, your investment is protected by real property, so your risk is extremely low. 

@Martin StreichPlease go to your profile page https://www.biggerpockets.com/users/msresolutions and click on your photo to update it.

for me, the ones that cashflow the most are the ones that I bought with 3% long term debt, they were new (low maintenance) and they are in high appreciating areas(just a bonus but does not impact cashflow).

It's no different than their 2-year, low interest rate teaser houses.

If he must attempt to get the low interest rates of 2021 on this deal, I suggest that he instead look for assumable loans.

Instead of moving into another single-family home, consider house hacking a duplex or triplex, this allows you to use low down payment loans (FHA, conventional) and offset your mortgage with rental income, accelerating your path to financial freedom.

When I was in college I got offered a job that was a pretty low level crappy position, but at the bank I wanted to work at. 

Option 3- If they have qualified for FHA; counter the offer to see if they can qualify for low downpayment conventional loan

So, go with a good solution on the deadbolt.Screw a lockbox in a wall near the door for an emergency physical key.Find a locksmith that can rekey the doors between tenants - put ALL locks on the same key.Most electronic locks warn you when the battery is getting low.

This has led to what’s commonly called “interest rate jail,” where homeowners are reluctant to trade their low rates for higher ones in today’s market.