Your risk vs. reward is way off balance there. 

Other risks, the contractor walking off the job, a storm hitting and delaying the project for weeks, someone breaking into the home and stealing stuff (which happened just the other day to a client of mine), a squatter, or drunk driver driving into the house (happened a lot at my old job as a firefighter lol).

If you take the heloc to pay off siblings, I would still offer a big "Cash Now" discount so that they get paid quick.

I would like to work out a payment plan whereby they pay me while I have control of the rights to the mortgage then in 10 years I pay off the principal.

My wife and I have designed over 100 projects in 11 states, so her design knowledge has also rubbed off on me a bit! 

A couple years ago, someone took the pics off my Zillow rental listing and made a fraudulent Facebook listing and was communicating with prospective tenants.

This STR would also be a place for us to block dates off for ourselves between work contracts (if we want to), which adds a slightly more personal investment in this one. 

Either way if it helps someone out especially going through what he mentioned it may add some gratitude and help him avoid further late bills.You can get more bee's with honey so in some cases it can pay off being a little more lenient. 

While rates may not decrease, the significant double-digit increases should level off.

Major issues are lack of parking, lack of elevators, leading to numerous unlived in units.