You can convert coordinates between layers using these monstrous expressions:
CanvasToLayerX("Player", LayerToCanvasX("HUD", x, y), LayerToCanvasY("HUD", x, y))
CanvasToLayerY("Player", LayerToCanvasX("HUD", x, y), LayerToCanvasY("HUD", x, y))
These will convert HUD layer coordinates (x,y) to Player layer coordinates.