Ok Crack Theory time...
I've been thinkng with some of the looks and actions of Violet that she may be Baby 5.....first off, their hair is extremely similar when you look at it from the back...they both have a similar poof look to it. After that, their Lips. Baby Five has defined lips that are covered with Make-Up. Violet happens to possess the same lip structure, but it appears as though she doesn't wear Lip Stick.
Next their personalities. Both have that extreme over the edge personality when it comes to love. When Violet claims she may end up falling for Sanji, it basically parallels the "Am I needed" line.
Also, Baby 5 mentioned she was in deep debt. Using her looks and dancing could be one method of trying to earn money. Based on the civilian's description of how people act when Buffalo was around, it is almost as if the Doflamingo pirates have some manner of honesty within Dressrosa.
Lastly...the request. She thinks Sanji is strong and thus wishes for him to kill a man (now is a good time to point out that Violet stabbed a man....Baby 5 csn make herself to have sword hands). This could easily be Doflamingo because she resents that he kills her boyfriends.
I know it is far fetched, but some things tend to line up...I can't imagine her real name is Baby 5 so I could see it as a code name for her real name Violet.