I’m curious if anyone has experience using a line of credit within a JV or other partnership and if so, how have you structured it?

@Bryan Clark I'd make sure all the systems and structure are in working order (i.e. roof, plumbing, hot water heater, heating, air conditioning, etc.).

Is there some sort of limition on this method?

I think you are referring to "cash for keys," be it through a formal rent control method,  or through ad hoc agreements with the tenants (cash and free rent for "x" period of time, etc..).

If not you either find another deal or structure it it to save you money.

I'm stuck in the mindset that maybe Park City or Garden City would work for AirBnB properties, but is it a method that works elsewhere?

Has anyone partnered with an owner to flip a house and if so I did you legally structure the deal?

I don't have the capital myself and would only consider creative methods for my own BRRRR or similar project down the road. 

However, my mortgage guy said that the way the properties are structured, (three parcels in one deed) they may be unable to do a market comp, as its very uncommon.

One upside of the DST structure is that the acquired debt is the responsibility of the trustee of the DST, not me.