nicki did
No.
Technically, yes. Nicki Minaj has debuted her acting career in an independent film called 'Stuck On Broke'. She is probabaly set to play the main role of Erica Payne in the upcoming movie "Charge It To The Game."
Nicki Minaj plays Steffie in Ice Age 4: Continental Drift.However, you are asking why, so my answer is why not?
Her favourite ice cream is pecan or cookies & cream.
dancing on it
yes
nicki manargi
Steffie the Wooly Mammoth. Steffie is the "brunette" mammoth that hangs around with the more popular mammoths. ~ Sources: IMDb, Ice Age Wiki
Yes, she will be, and is been confirmed that Keke Palmer will voice her.
Steffie the mammoth!! 
Yes, she does, and she voices Steffie.
Yes, she voices a woolly mammoth named Steffie.