FHA Loan Mutli-Family Investment Question?

[Joel Bowen]

Hi guys, I am brand new at real estate investment. I am still just researching as much information as possible at this point. I learned that if I were to use an FHA loan to purchase my first property I am able to purchase a multi-family unit that has up to 4 units. I just finished reading this article by Frank Defazio (http://www.biggerpockets.com/renewsblog/2012/11/08...) 

and he states that after a period of time you can move out of the property and rent out of room you were living in to generate a higher cash flow. Is it legal to purchase say a 4-plex and never live in it at all with an FHA loan? My parents have a property with an extra unit that I can stay for free and I don't have any real estate in my name. My address is registered currently to my parents address. There would be no reason for me to move into the 4-plex unless I legally had to, to secure the FHA loan.

Second question, If I do legally have to live there, How long after living there can I move out so that I can generate extra cash flow off of the 4th unit?

Thanks in advance guys!