I feel I now have a team that I can lean on, with minimal traveling at this point. 

If this is already a duplex, then it seems you're not dealing with a single family zone, so the difference between 2 units and 3 units seems minimal in legal worries with zoning at least. 

How can I begin flipping houses with only $10,000 minimum?

Make sure that you are qualified so that you don't waste anyone's time and get a bad reputation in the market place.

Now I am trying to decide if I should sell it or hold off for another year with minimal to negative cash flow to ride some more appreciation/inflation and stay within my no capital gains window.

If you want to work with a Buyer, you should have a written agreement that ensures you're not wasting your time.

Or they don't qualify and waste our time.

I got a card with minimal of 200 bucks thru the link you provided.

If it’s listed on the MLS, doesn’t hurt to have a candid convo with the realtor so time isn’t wasted on either end.

I understand you can save 4-5% on broker fees, but getting to even minimal cash flow on a deal seems like you'll need 20-30% discount to what's on MLS in this market.