They walk the very edge of what's legal and step way over the line for what is acceptable business practice as well as just plain ethical.

Any input on how I can best meet the tenants needs without stepping over any legal or ethical boundaries?

You may want to check out the code of ethics, ARS, and commissioner's standards to see how they may alter your current way of handling buy/sell business and investments.

These are professionals with additional training and a stricter code of ethics.

What's missing is the ethics involved IMO.

I have learned this the hard way as I put allot of time and effort trying to help a new investor to just have them have no follow through or the work ethic needed to succeed in this business. 

I would never do that.Real estate should be an ethical business.

@Luis CarreraI don't see an ethical problem in doing this.

Also I think being regulated by the rules helps you steer clear of some of the less than ethical tactics that are commonly put out there to aquire properties.

@Alex Craig is an ethical businessman you'll be safe with him, (and several others here),  but never just hand over your money relying solely on their offer of a house.