I'd then structure the deals such that if/when the homes are paid off I'll be at retirement age and can simply change income streams.... just the real estate version of accumulating wealth to reach a FI number, then transitioning ones portfolio from a growth focus to a yield focus: a very well-trodden process for stock market investors who "retire early".

Look for building multiple streams of income. 

I’m of the mind set that I want to invest my salary into assets to create multiple streams of income.

You can find videos on Youtube teaching you how to calculate your return based on future streams of cash so make sure you learn that and analyze each deal with what return you require in mind.   

While I love my job, and have no plans on stopping it...kids can be expensive and increasing my revenue streams is desirable.  

Their income is not what it needs to be and they’re looking for additional streams.

Add in land acquisition and development fees (I would guestimate $25K per dwelling but a builder (I'm not) can chime in) then you'll have a ballpark figure per SF. 

For people with multiple streams of income and different investments, I always suggest getting a CPA.

Renters insurance and my own commercial/rental and dwelling insurance. 

Account Closed My lender is able to finance as a multifamily dwelling with no issues.