I noticed in your PIXI documentation you have:
Creating a sprite
my_sprite = PIXI.Sprite.from("mysprite") stage.add(my_sprite)
This tripped me up for a minute before I realized it needed to be addChild instead:
my_sprite = PIXI.Sprite.from("mysprite") stage.addChild(my_sprite)
Btw, this is an awesome thing you're building here. Keep up the great work!