Sprite instances share the same texture set.
Your example is working as intended, but since you have only a single frame, for multiple instances, only the latest frame loaded is loaded and displayed for all instances.
Add as many frames to your Sprite object as you will have elements in your array (in your example, you need two frames, make sure to set the animation speed to 0).
After the create action, add an action that sets the current animation frame of your sprite to loopindex and then load from the URL.