That is from a legal prospective. 

Set very clear expectations, since they're living in the house with you think through how you expect the arrangement to work and make sure that's communicated to prospective tenants prior to move in.

Your friend will have to prospect to find leads (new realtors, lenders, attorneys and other "funnels").

Within your target investment market, you'll need to identify an investor-friendly agent/broker who can provide you with the insight you'll need to assess a prospective deal.

This will help build your credibility with prospective clients.

With commercial, your volume of prospects is much lower. 

Similarly, we learned that just because a contractor has a higher price and a big business does not mean they will be professional or reliable in unexpected situations such as our local permitting process and sending in the proper forms to pass inspections.Only higher contractors that are references from trusted sources.

I bought a vacant lot and had the ball rolling with everything that needed to be done to do a new constrcution, permits approved last week which the company that was financing the build was waiting to start issuing the funds.

I believe you are correct, "odd jobs" that are less than a certain amount of normal pay are still permitted.

The market here on Oahu has so many non-conforming properties that have say an extra wet bar or extra non-permitted bedrooms.