So, as you note, hopefully there is still enough liquidity/cash flow in the deal to keep it afloat long enough to ultimately pay off (or at least make all your money back).  

Year 1-3.We have 4 kids all older between the two of us.Our ultimate goal is retirement and generational wealth.Each kid will inherit one duplex and we want to teach them as much as possible.Does this sound like a good plan,Or am I missing anything?

Ultimately the more value you can add to the transaction the more favorable of terms you can negotiate in a partnership.  

Start by reading the Ultimate Real Estate Investing Guide: https://www.biggerpockets.com/guides/ultimate-real-estate-investing-guide/introduction2.

They can pay off property before loan comes due and have ultimate flexibility when to sell or refi.    

It's making me want to be very cautious on my expenses & ultimately not want to put forth the usual effort as my work is not being fully appreciated.  

However, I recently stumbled upon an intriguing concept called PadSplit that allows you to leverage the multifamily concept within a single-family property, ultimately maximizing income potential.

I know they are duplexes everywhere, and I know ultimately depends on your choice of city.

Ultimately think long term and think about what you want to get out of this. 

In order to get out of Freddie Mac's "Limited Multifamily Experience Sponsor" category, you must have ultimate ownership & control of either (i) 3 multifamily properties [1 of which you've owned for at least 2 years], or (ii) 1 multifamily property which you've owned for at least 5 years.