Bottom line is no direct or INDIRECT benefit between the plan and disqualified parties.As noted in prior posts:The use of debt-financing will create exposure to UDFI taxation.Rental income is passive in nature and fully tax-sheltered.  

Are there ways to be "better" than others in direct mail?

@Ben N.The law states there may be no direct or indirect benefit between a plan and a disqualified party.  

Even commissions (in an indirect way)

This way I can indirectly teaching my wife the fascinating side of investing.

You'll want to invest in direct marketing as well as growing your network.  

My municipality defines a business as:"Business means a calling, occupation, profession, or activity engaged in with the object of gain, benefit or advantage, either directly or indirectly." 

Always have a contingency  line in your estimate for a loan of about 10% for construction and closing costs.Try not to forget about all direct an indirect expense.  

At my parents house I almost had to put it in direct "line-of-sight" with the lock because the walls would "kill" the signal. 

An IRA may not directly or indirect benefit lineal family.