I love the name Samara, it's DD2's middle name. It has very special meaning to me. The Samara I knew was both Sam and Sami and she was gorgeous. A bubbly beautiful girl I'd go with Samara as her name and shorten it.

DD1's name was picked because we liked the nickname first and worked backwards from there. She's nearly always know by her nickname but she's always introduced first by her real name. Funnily enough, she introduces herself by her real name too.