I've got about $525K in equity in the property, but lenders have told me that I cannot get a HELOC to access that equity for additional purchases because the duplex was financed as an investment - they have said TX law dictates that HELOC can only be used on primary residences.

The era of "everything prints money on Airbnb" is LONG GONE! 

Depends on rhetoric vs reality.

Does anyone in the field have any advice or insight on the business to beginners?

Specifically, I'm seeking talented handymen to work their magic on light cosmetic enhancements and an ingenious stage designer to infuse the space with their creativity.

One particular property that I looked at was converted from single family with a one bedrom unit on the first floor and two single room apartments on the second floor. 

I wouldn't start investing in the US if you have no plans on coming back from living in China.

Determine the price that attracts the investor, stop the bleeding and and move on.

(The Black Friday sale on the Bigger Pockets bookstore was where I did my own Christmas shopping so my family knew what to ‘buy’ for me!).

I need more advice
Just now I suddenly had an idea, the land left by the LA fire and SB-9 (SB-9 allows single-family residential lots to be split into two lots)
Is this a good opportunity?