I think you should seriously consider your financial goals and strategies.

Market Selection: What factors do you consider when choosing a profitable location?

When you are creating notes from the start with the intent to sale, you can also consider a 1st/2nd structure that can help you achieve similar results as a partial but start getting cash flow sooner. 

I'd need the interest rate to be roughly 5% to breakeven on an interest-only loan, and was considering a balloon payment in 5-7 years.

Personally I wouldn't feel comfortable trying to wholesale a relatives $1M home knowing that I am breaking the law if I cross over into doing anything that can be considered representing them in the transaction, and knowing it will only be marketed to people who buy properties wholesale (typically investors who don't want to pay retail prices), instead of the majority of retail buyers active in the market who are typcially willing to pay more. 

Stay disciplined and avoid rushing into deals without thorough due diligence.Resources for InvestorsIf you’re new to investing in distressed properties or looking to expand your portfolio, consider leveraging resources like:Local Realtors: Realtors specializing in distressed properties can assist in locating off-market deals and navigating complex transactions.Community Forums: Attend a local investor meetup or join online forums for the Phoenix market.Educational Tools: Search out webinars, workshops, or courses on investing in distressed properties.Final ThoughtsThe distressed property market in Phoenix is creating some excellent potential for the right investors willing to go the extra mile necessary to take on strategic risks associated with this category of real estate.

Since we are considering a 4 bedroom house, let's compare it to a 2 bedroom 2 bath duplex each side.  

Investors should fully understand that Section 8 is not a cure-all for Class C & D tenant challenges, it's just trading one set of problems for another.We see too many investors not doing enough research to fully understand all this and making naïve investing decisions.

It’s worth considering self managing as a STR for depreciation benefits if the demand is there 

If managing it yourself feels unsustainable in the long run, hiring a good property manager could give you more peace of mind.Since a 1031 exchange or like-kind replacement doesn’t seem to be a good fit for your current situation, you could consider a HELOC if you need to tap into the equity for other investments without selling the property, although rates are high so this would eat up your cash flow.