It's very unprofessional and unorganized, and defeats the point of having a PM.

This philosophy of managing the PM defeats the whole purpose of having a PM.

But if I still need to put 20% down at the time of the refi it defeats the purpose of BRRR.   

@Brian Garrett yikes, this is a very self-defeating attitude.

Seems like it would be a good way to increase cash flows while scaling down a portfolio so you could hold fewer properties as you get older and have higher cash flows but still defeating tax if it’s allowed

It's currently fine where it's at and also, transferring it to my name defeats the purpose of a 'sub-to', doesn't it?

Which really lowers you Cash-on-cash (COC) returns, which defeats the purpose unless you are looking for an appreciation play, which is a little risky at this part of the cycle. 

This can be quite complex and you are in essence getting taxed on a tax deferred account (defeating the purpose).As Dmitriy pointed out, having your partner use their IRA to fund the deal as a note and deed of trust will avoid this taxation to his/her IRA so all you will need is loan docs drafted and executed.

Like @Tim Swierczek mentioned paying rent while saving for a down payment on a future duplex seems to defeat your ultimate goal of house hacking now.

That's just double the work (and expense) and it defeats the purpose.