Even more obvious when a real name Google search lands on this post.Your other angle of buying an investment and later trying for FTHB on your primary is a great idea and one you should check with a tax pro on (ie, not HR Block).If you can use the plan, then start cramming every dollar you have into an RRSP so you can use that money tax-free come time.

@Evan Greenfield:I'm a buy and hold guy....Neptune or Atlantic Beach area is primary.  

@Yadira Gutierrez You never mentioned a construction to perm loan....wrap your primary and do a hard core rehab or build a house...good times. :) Best of luck in whatever you decide!

I'm planning to apply for mortgage for the fourth home as primary residence(CA), Will I be able to have mortgage interest deductible since it will be my primary residence?

Since you'll be "flipping' your primary, how will that impact your other flip(s)?  

I currently own my primary residence worth about 90,000$ I also own a rental property out right worth 110,000$ I currently recieve 650$ a month for my property after the management free.

Usually accessory structures are limited to 30% of the rear yard and must be accessory to the primary structure.

When you submit an offer to the bank on an REO there is usually a cover page and with Homepath there is an affidavit stating whether or not you intend to live full time in the property As your primary residence. 

I'm reading a book and the author mentions the primary residence capital gains exclusion.

In order for that property to qualify for both the `primary residence exemption and sec 1031 it must be a current rental that you have also lived in for 2 out of the last 5 years.