Egomassive should have an actual answer to this.
In the meantime since I'm here, try this.
1. In your "World.ini", in the [World], you should find "Character= Juni" tag. To change the initial character, simply change "Juni" to whatever the file name of your character is- "File's name. file extension".
If you haven't already, before that, you need to add your character's .png file into the "Custom Objects" folder in your world's file. Afterwards , write in the [Custom Character] "Imagen="File's name"."file extension" (where as n=any number, file's name is the name, and file extension of the image which I presume is a .png). If your custom character is unintentionally invisible, you've done something wrong.
2. I'll leave it to him.
Well, good luck.