The fix/flip might be a good way to get such a relationship started: usually has lower cash out of pocket requirements and you can sell the property faster to recoup the capital invested, plus any profits.

It could include selling well below market value, giving a majority interest to your partner (like 51%).

You can negotiate a flat fee, or percentage of their profit of any deal. 

Any profits from the flip return to the SDIRA tax-free or tax-deferred.

Proximity to Major Northeastern CitiesBuffalo’s location near major urban centers like New York City and Boston makes it an attractive alternative for buyers seeking more affordable housing without sacrificing access to urban amenities.5.

If the way to increase the selling value of a MFH is to increase NOI by increasing income or decreasing expenses; why are the majority of sellers putting their properties on the market with under market rent?  

Even now there already starting to call out for private and non-profit sector to, yet again, clean up and solve everything Big Gov botched, yet again. 

But then again a large swath of syndicators that jumped in when they did have had major struggles to full blown liquidation and 100% capital loss's..

I know you said you don’t expect anything major on the properties soon, but I would take a careful look at what is most likely to need to be replaced soon and figure out how you would pay for that if it needed to be done tomorrow.

But, the profit margins look to be eye-popping, sometimes on the order of 10X or better.