When you duplicate a Node, value passed information are copied, and reference passed ones are "linked". To unlink the texture, simply set the texture property (on the right side) to a new texture object, and then change the associated image. For the script, clear the script and set a new one.
If you want to create many independent custom Nodes in the editor, you can put a
class_name Ork in the script of your Node to have it appear in the Node selection when adding them.
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