Since your going to engage other sales folks to bring you the deals and  take care of you long term  IE  PM etc etc. 

Their extensive networking, both regionally and nationally, is invaluable in navigating the complex lending landscape.Secondly, engaging with local banks and lending institutions can be highly beneficial.

Therefore, one might need to use more engaging tools and afterwords delve into books.

There are many avenues to exhaust including here, your local REIA and your state multi housing association prior to engaging a paid coach.

- Should I ask for proof of funds before I engage?

As long as it isn't for their personal purchase.Per RCW 61.34 a “Distressed Home Consultant” does not include: A financial institution; a nonprofit credit counseling service; a licensed attorney, or a person subject to chapter 19.148 RCW; a licensed mortgage broker who, pursuant to lawful activities under chapter 19.146 RCW, procures a nonpurchase mortgage loan for the distressed homeowner from a financial institution; or a person licensed as a real estate broker or salesperson under chapter 18.85 RCW, when rendering real estate brokerage services under chapter 18.86 RCW, regardless of whether the person renders additional services that would otherwise constitute the services of a distressed home consultant, and if the person is not engaged in activities designed to, or represented to, result in a distressed home conveyance.   

This way, you can engage directly with individuals and gain insights from their experiences.

Transactions conducted or attempted by, at or through the bank (or an affiliate) and aggregating $5,000 or more, if the bank or affiliate knows, suspects or has reason to suspect that the transaction:a. may involve potential money laundering or other illegal activityb. is designed to evade the BSA or its implementing regulationsc. has no business or apparent lawful purpose, or is not the type of transaction that the customer would normally be expected to engage in, and the bank knows of no reasonable explanation for the transaction after examining the available facts, including the background and possible purpose of the transaction.

People looking to engage in this way can go to FB, reddit, etc. or the comments sections of their favorite 24-hour news channel. 

 #1 has me engaging a lot less lately.