Chalk up a day of standing in line. 

Call in with a credit card and the person on the other end of the line will determine your disability with a 30-minute phone consultation.

I plan to put up a fence around a duplex and would like to get a better understanding of my property lines.

-  in addition to the two options you listed, I would likely also be considering an FHA owner / occupied multifamily, as this could be a great cash flow generator down the line. 

Have a portfolio lender in mind, few PMLs, and potential line of credit.

Add a line to the lease that states your process on this.

Tenancy is what you have whether it is JT, JTWROS, TIC (not the product, the ownership), or what have you. 

There is no risk in establishing the HELOC (assuming you one can be responsible with such a thing) - its a line of credit, not a loan.

Items like forming an LLC, getting a logo and a website, business cards, finding people you can work with (contractors, lenders, real estate agents, real estate attorneys) to support your efforts etc.The bottom line is this stuff takes time - so be prepared to give your patience a workout!

Adding further to the frustration is that I'm often asked if the property is rented out currently and if not, we have to do an entirely different insurance product while the home is being fixed up.