If the investor would like to sell the property, we will split the profit of what it sells for 60/40 (the investor getting 60% of profit while I receive 40% of profit.)

Because I need cashflow proceeds to start being withdrawn in 2 years and not today, I'm looking for how I can build up the empire with a larger portfolio with continued investments beyond the initial $250k now.  

Aiming for larger properties on your first deal (100+ units) is definitely very ambitious. 

However if you didn’t calculate in at least some percentage of the rent for vacancy, repairs, and CapEx then eventually things will happen, such as a vacancy or a repair being needed and you will be out of pocket a much larger amount of money than just your $400.

You never get hurt taking a profit.  

If you can get it dirt cheap somehow and maybe flip it, then you could profit. 

Network in person, see if they have a publication where you can post your deals and what you are looking for, and if there is a larger annual conference for investors locally consider getting a vendor table to talk about your business and what you are looking for.

Turnovers and vacancy kill a rentals profitability.

It's not quite as profitable as doing AirBNB yourself, but at least it's a stable income. 

Honestly, I never fully understood what they meant—until recently.I’ve been diving into some larger-scale real estate projects, specifically in commercial properties and multifamily development.