Biggest clauses are: who's responsible for what, what are the penalties if someone doesn't perform their duties (including forcing them out) and what happens if one party wants out and the others don't.BTW: your brother should do this with his new girlfriend BEFORE paying part of her mortgage!

Also, with the shift toward focusing on cash flow, are there any specific markets or types of properties you’re seeing that perform well, despite the challenges?

It is very common in the investment advisor space. for example, if I find an investment advisor and want to know how his client's portfolio has performed last 3 years they do not make that  information up, its verified. 

Performing a cost segregation study on these types of properties can offer additional tax savings.

For example DSCR (Debt Service Coverage Ratio) loans look at tax returns to see how a property performs in terms of income and expenses to see what loan amount is justified. 2.

Owners mistakenly ASSUME all PMCs offer the exact SAME SERVICES and PERFORM those services EXACTLY THE SAME WAY, so price is the only differentiator – so, they often select the first PMC they call or that calls them back!

If your goal is to get into short term rentals - analyze the deal to a point where it can still work as a longterm or midterm rental if short term doesn't perform as expected. 

We perform several flips a year when we find them from wholesalers.

I bought a non performing note, the borrower sold the property sub-2 where the new buyer reinstated the loan but because of the transfer I am calling the due on sale clause.

If the answer is performance-related, or due to the agent simply not being a good fit, then that is understandable and they might let you go if you explain your legitimate reason honestly and ask to be released from the contract nicely.