You may also have usury laws to contend with in your state depending on the type of property sole and transaction.Another matter related to interest is that a seller can not charge points, that is pre-paid interest and seller financing is an installment arrangement loaning equity based on a sale price, not cash.In serving your client's best interests, it is better to advise competent assistance by a professional, such as a CPA would in a legal matter.

Well, I'd contend you could change the word "house" in DR quoted "List your debts, excluding the house, in order" to "houses" and still follow the fundamentals that DR preaches.

I have contended that comparing large apartment complexe's OE and NOI to SFR's is an inaccurate comparison.

If we must assume an owner was an idiot, not of sound mind, not prudent, then we have other issues to contend with. 

Though my brother is down the street and will be watching over the renovations for me.Yes, rent control in the Bay Area seems like it would be a lot to contend with!

One of the places I have always liked is Colorado, and Colorado Springs is one of the top contenders in my list (perhaps Fort Collins too, but prices are already very high in FC and it's relatively smaller, so CS probably wins over FC). 

3) In which metro of the top contenders it's possible to find a cash-flow property?

The more you learn the better before you talk with the final contenders for your service. 

Their down towns are directly adjacent to the worst areas of the cities, the "French town" of Rochester next to downtown is a C- neighborhood, at best, and is a contender for worst neighborhood in the state (though the tree streets of Manchester probably win that title).

There are very few HOAs to contend with.