The asking price is $80k and I'm securing a conventional loan with an assistance loan for the down payment and closing costs. 

The monthly payment was identical to 5% down due to rate differences.

Remember though, you get appreciation on the market value, not equity, so if you pay 25% down, you will see 4x the appreciation as a return on your down payment.

Use them like a sword to cut out the bad deals! 

You get better terms on a primary residence -- lower interest rate, lower down payment requirements -- because if you encounter financial strain, you're most likely to pay the mortgage on the roof over your head.

I have no investment money currently but aiming to save for a down payment in 2024.

This will help you figure out whether or not her partner even has the credit/income to support his portion of the rental payment. 1 - Yes make him fill out an application with conducting credit, income, employment check, etc. 2 - Yes.

Payments are $2k per month.

I usually hear of a 5-10 year balloon payment.

We don't mind whether the ballon payment comes from the sale of one or both of these properties or from one of our active flips we currently have going on.My questions are:How does the contract, or contracts, need to be written to give us the ability to list/sell these houses after we fix them up within the 4 month time frame.