However, there is a balloon payment at 18 months in, where the current owner expects to get paid off.

Hello, Thank you for taking the time to read this.

I've been trying to have one tenant do the autopayment for 8 months now and it has only worked one time.

This may sound harsh, but I would actually put this on the tenant to get his rent payment back.

Yes you can use commission as sourced funds for down payment on a conventional loan.However some lenders have internal overlays that don't allow it.

As long  the tenants pay the rent each month, increasing their rent will be very tough and getting them to leave will be extremely tough. 

They have had a difficult year and are struggling to make their payments on time each month.

The property rents for about $4K/month total.

Also, I am assuming since you house hacked that you only did 5% down, which then increases your mortgage payments compared to 25% down buyers.

Pyment is $1,054, but $625 is interest.If you sold current house and bought new one with same mortgage amount, but current interest rate of 7%, the payment would be $1,663, interest amount $1,458.So, the interest cost difference would be $833 month!