@Chloe Salcedo why aren't you focused on working with your sibling and learning as much from them as possible?

if all properties you see are below market rents, than I don't think they are really below market, typically.Beyond the cost of vacancy, renovation budgets, etc that come into play.  

Are they doing everything possible to expose properties to the broadest possible market?

One thing to remember is the flipper will have $30k- $40k in financing during flip and closing costs to buy the home then another $25k when they selll so that will play into the numbers that need to be considered. 

You will not have the rate long enough for it to interfere with your current and proposed profits.This is where having a good team comes into play for example having a seasoned realtor who knows the market on the purchase/ARV side.

A tiktok live of a dude playing a long haul truck driver simulation.

BiggerPockets also has a calculator to analyze deals, and I highly recommend you start this as soon as possible, even if you are not ready to buy.

It can be done ethically, but you need safeguards to confirm mortgage & possibly property tax payments made on-time, as well as insurance with you protected.- Also, you need a legal way to take back the deed if buyer defaults!

@Johnny Lynum we did offer them an aggressive cash for keys amount to get them out as soon as possible.

He makes sure you have every resource possible.