Is there any tax benefit if I move back to my rental property for a few years before I sell?

Hi, I bought a house in 2000. I stayed there until 2015 and turned it into a rental property. I'm considering to move back in for a few years before selling it and move out of state when I retire. I read the Housing Assistance Tax Act of 2008 has changed how the capital gain exclusion for primary residence is calculated. I have a few questions:

-- Is it correct that I have to convert my rental back as my primary residence for at least two years before I can claim any capital gain exclusion despite the fact that I lived there from 2000 to 2015?

-- If I move back into the rental for 5 years and sell it in year 2030, how do I calculate the nonqualified use period for capital gain exclusion? Do I start with year 2000 when I purchased the home or end of 2008 when the Housing Assistance Tax Act of 2008 took effect? If I start with year 2000, I have 20 years of qualified use (2000 to 2015 and 2025 to 2030) and 10 years of non qualified use (2015 to 2025). If I start with end of 2008, I have 12 years of qualified (2008 to 2015) and 10 years of non qualified use.

-- I'm married but the house was bought when I was single. I have never filed a quit claim deed to add my wife into the title. Do I need to add her name to the title in order to qualify for the $500,000 capital gain exclusion? 

 

Any advice will be appreciated.