and you cant split a duplex into two halfplexes... they did this to preserve rental stock... this is a major YMMV situation.  

Would be curious to know about single family as well just so I know in the future. 

@Matt Millard If you take a self directed Roth IRA with checkbook control and buy single family homes at the right price you will beat the pants of any insurance policy or stock out there.

Have you checked the master plan for the area to ensure that the city hasn't designated the area for higher density in the future?

Needless to say, we probably won't be accepting any offers from her in the future, unless we don't have any other offers in place.

At this point, the HELOC isn't urgent, but would be nice to have in case I needed it for a future opportunity.

I am excited for the future and ultimately the financial freedom to be able to travel the world to my hearts content while investing back in the communities in a variety of ways. 

I reside in Hotlanta, the future home of Amazon’s HQ2 (fingers crossed)!

If she's got a business though she is able to reinvest any profits back into the company or she could buy stocks with it, etc. and wont need to claim income until its cashed out to herself I believe.

If you think there will be another recession/depression in the future that would bring house prices with it, sell.