You seem to have done all good.
- Creation of an interchange blueprint pipeline and override of the ScriptedExecutePipeline
- Adding it in the good spot in the Pipeline stack: FBX use the default pipeline, unless you override in a per translator pipeline, so that is the correct space. You also put it after the DefaultAssetsPipeline so that is perfect. We need to have DefaultAssetsPipeline do some work before running your custom pipeline
- It will show in the list of pipelines used in the “Assets” stack. You are not executing one or the other, it is all of them that are executed in order. That is what we want: First Execution of the Default Assets Pipeline that will do most of the work of the import then your custom ImportAnimation sequence comes and modify some settings on the factories to change the asset names. Because, ATM, your pipeline does not expose any properties nothing shows in the window when you select it.
Now I am not sure why it does not work, I am trying to get the real name from a SkeletalAnimationTrackNode, that might not be what should be done in your case.
You could try something like that that does not use the original track name. Just to make sure the code does something
Then if you can share one fbx with me to test?