Because of another deal I am financing I dont have the cash on hand to do the deal and while I have the equity to do a HELOC, I do not want to apply for the Heloc until my current deals funds. 

I have used this strategy personally more that 10 times and helped many clients doing it.

You'll need a contract made up between the two of you and a loan doc for the funds.

Regular reconciliation of accounts and maintaining a clear separation between personal and business finances is crucial.

You would of course not deplete all of your cash reserves on the down payment in order to service the monthly debt payment and carrying costs, but this should give you an idea of what you can accomplish now if the time is right.Many hard money products offer 100% funding for rehab costs so you would not need to save for this portion of the BRRRR project.

Used personal funds for literally everything.

There also could be tax benefits and fringe benefits like personal use.Good luck!

If you have back rent, take the person to court and get a judgement and garnishment of wages. 

If they offered seller finance to us, those funds could then be used to pay for the lease at our home if we swap however they are retired, what about tenant screening amongst other things, not sure what type of deal structure is best for this scenario but if anyone can guide me with any feedback is greatly appreciated.

Evaluate market conditions closer to your next move to optimize the timing for a 1031 exchange.HELOC for Investments: Utilizing a HELOC could provide funds for a down payment on an Airbnb or potential flip.