Quote from @Scott Mac: It might be the investing environment.Right now we have a different interest rate picture then we had a few years ago.

I can mark it up with a fee or by increasing the rate (or both, but I never do).

I don’t really have an interest in House hacking if long-term rates are $700 a month incl utilities for a bedroom. 

Do you think this strategy gains strength if lets say... in five years interest rates are at 5.5 vs 7.5 now?  

In this market, I would not finance a first time flipper at 75% profit split because the profits and success rate is lower than the last dozen years.  

Higher inflation equals higher interest rates. 

We're exploring creative ways to provide him with the cash needed for the down payment while avoiding triggering a taxable event.One strategy we're considering is purchasing his future primary residence ourselves, making the mortgage payments, and then, once we've built enough equity—comparable to the appraised value of his rental properties—transferring the title to him as a form of exchange.What are your thoughts on this approach?

Incensed deal flow by developing a large list of contacts of commercial mortgage brokers using LinkedIn.  

A few months ago my fiancé and I bought our primary residence and we did really like our mortgage broker.

Maybe a mortgage lender can chime in.