Mavie En Rose - (non)sexual Pedophillia

What is the significance of the usage of a transgendered child instead of an adult?

In my opinion, two things arise out of this usage. First, an air of innocence is able to surround the character as a child whereas an adult may have had a much more negative connotation connected to them by the audience. Second, the young age allows the disconnect from transgenderdism and sexuality/sensuality. This is very important in allowing a much less biased message to be put forth. Sex, especially in the United States carries too much behind it to allow a sexually active transgendered individual to be judged fairly.

Is Ludo's identity a result of peer influence or is it something else?

Ludo, as a whole, has many influences. A very prominent one is the t.v. show that he watches. Femininity screams forth from it in the stereotypical sense and the effects are evident in Ludo. He dances like her and dreams that he would be in her place. This is not his only influence though. He feels different from the other boys, such as his brothers. Instead of developing an image by having similarities with his brothers, he indirectly sets himself up as an opposing image of the typical boyish child. The power that the television show has had over Ludo isn't completely explored, but I personally feel that there was something, some driving force, that made Ludo feel that he was not a boy inside. While this is debatable, one will never be able to actually say one way or the other and must instead make simple speculations.