If you're working with a tax pro, they should be able to run a comparison for you to show the differences.

Third, they pushed him to buy device from a tax person asking for $600!!!!

If you read and understand the instructions for a 1040 tax form schedule e, you basically now understand how to make money renting out property.  

4) Applicants over 18 - what about full-time college students still being declared as dependents on parents' tax returns?

They can be written off in one year depending on tax law updates. 

Once it is an investment property then you can sell it using a 1031 exchange which allows you to defer capital gains tax, and use that equity to buy new investment properties.

Law: Illinois has a law that requires (I believe) the insurance company to give a 'General and Special Taxes & Demolition Expenses' Form (Important info for this issue) to the city when claims/damages are over a certain dollar value.

Any deferred maintenance concerns?

Pm, property taxes, insurance.  

BUT you have less red tape, no tax returns, DTI, or employment checks are required.