Namiss talent section of pageant?

Go with the dancing. Unless you are a very experienced singer with a voice coach and are SURE that you will knock the judges' socks off, don't sing. Especially "At Last", even professionals have a tough time getting Etta James songs just right. Also, dancing is dancing, but different judges have different things they like to see in singers, when it comes to singing they generally either adore you or hate you. Trust me, do the dance.