HELOCs only make sense as short term funding - especially with rates where they are now. 

Hey @Adriana McLaughlin - This is actually the FIRST TIME I have heard of the term "ALL-IN-ONE-FIRST-LIEN", but after doing a little bit of reading on it I am not sure I still completely understand.Basically, you apply for a HELOC credit payoff your existing mortgage with this variable HELOC and then in theory have some leftover as well...so the advantage is paying off your loan early and getting access to a line of credit, but the disadvantage would be a variable rate mortgage for the reminder due on your orginal first mortgage? 

I then thought of the idea to offer they a fixed rate if they private lended me cash on a short term (5-10 year) period.

- Replace the flushing mechanism about 20 bucks or replace the toilet with a water efficient one if holding long term. 

Their longer term goal is to use the money you give them to put you out of business.  

I do large renos, short term (AirBnB / VRBO) and Mid term (traveling professionals) rentals.Have so much fun.Ron

But if you are trying to teach yourself pivot tables instead of hunting for deals or managing the properties, then these are a detriment.The thing with any analyses you perform, they are ultimately done for the benefit of the people viewing them.  

If they are in the lease term then they are responsible until it expires.

Long term rentals, short term rentals, flips, etc.  

@Renzo Roffmann property taxes alone are not a reason to sell.RE investing via rentals is a long-term process.Advise that you wait a bit longer and really work the property before making a hasty decision.Can you also STR the lower unit?