Dialogue box question

This script is made to show portraits of the characters, not the characters themselves.

I don't know the setup of your game. Are there characters in the game walking around, or is it more of a first person view and you use characters only for the dialogues?

When using portraits, not the characters themselves: add portraits of the characters as buttons to the interface with your textbox. Assign a value for portrait_index to that button and change name and value according to your settings in the script.

When using characters you could set the postion of the character so that it aligns with your box (but you would have to do this for every scene), leave all directions of the character empty, only add an image to the talk outfit. Then the character should appear when talking. But keep in mind, that the interface is above everything in the scene including the characters. So the characters can only be on the side, above, below the text box, not in front of it.