It is currently being rented out, the existing mortgage on the property is as a primary resident.

>We are targeting a CF of $400-600.I do not want to be discouraging, but the reality is at your rent to cost ratio you are very unlikely to be able to hit that cash flow without being very active in the management and maintenance of the property.I suggest you learn why the 50% rule exists.

I'm hoping to buy an investment property (duplex or triplex) with owner financing and wondering what if any options exist to find a loan to cover part of the down payment?

You're the one managing all of the details, committing your discretionary cash to keep up with taxes, insurance, etc.

He says that there are low money down lending opportunities that exist for people who intend to live on the property as their primary residence.

The STRs are tough with the Airbnb regulations ever changing, but if you find a pocket that allows them (and those exist for sure; we follow those laws closely), then you can do really well. 

If you use private money it's very easy to add the partner to a new or existing LLC via an operating agreement.  

I'd love to spring board off of our existing property to build our family's future and [hopefully] with the bonus of not being dependent on art for the majority of my income and subsequently fall back in love with making art again!

The 1031 was cut on everything except real estate by the last admin- Don't count on it existing forever.

Plus the cashflow is more important than the time commitment once I get it rolling from what I've read.