What if an investor wants to invest in a QOF with dollars from ordinary or passive income sources as their initial investments/ contributions into a QOF?

You may get lucky and find an "occupied" property vacant.If not, you'll get your best results offering cash for keys for a property delivered vacant in broom clean condition on a date certain.If you need to evict you may save some money vs. cash for keys but that definitely does not mean it's the better strategy financially.

Keep in mind a lot of the people your networking with often become deal sources in the future.

As @Todd Dexheimer mentioned educating yourself is key.

Other than that, I have not found an alternative source of financing.

My agent is really key  one big way, she hasn't brought me a deal yet with less than 70k profit.

I have a short "investor resume" that I send to all of my potential deal sources.

A key difference with section 506 investments concerns the products themselves: they are not regulated by the SEC and Investment Company Act of 1940 which governs stocks and mutual funds.  

I don’t have an answer BUT Zillow is not a reliable source for estimates

Additionally, getting down payment assistance from an outside source can get tricky as well.