Is double duty an incorrect phrase for host of Dancing With The Stars?
Double duty refers to having more than one job at the same time. The host of Dancing WIth The Stars is Tom Bergeron. Tom Bergeron is the host of America's Funniest Home Videos.
The answer is no.

Did Methuselah live at least 800 years as long as Sarah?
The biblical Sarah lived to the age of 127. The biblical Methuselah lived to 969 years of age.
The answer is yes.

Could Lil Wayne's children ride in a Chevrolet Corvette ZR1 together?
Lil Wayne has four children. A Chevrolet Corvette ZR1 has 2 seats.
The answer is no.

Can food be cooked in the cosmic microwave background?
The cosmic microwave background is faint electromagnetic radiation in space that is a remnant of the Big Bang. Food can be cooked in a microwave oven, but not in the remnants of space radiation.
The answer is no.