So, if I understood correctly:
- you have both normal meshes and linked meshes in the same slot
- you made animations for the normal meshes
- you made animations for the mesh that you turned into a linked mesh
- your linked meshes are in a skin placeholder, and your meshes are in a different skin placeholder, but both inside the same slot
- you did not replace the meshes with linked meshes by editing the path of the linked meshes and placed those in the skin placeholder of the meshes with animations
- you did not change the visibility of a skin placeholder in setup mode when you created the new linked mesh making the linked mesh skin placeholder visible instead of the mesh skin placeholder
So you should have two skin placeholders, and the mesh skin placeholder active in order to see both the animations of the meshes and have a backup with the linked mesh;
But the correct thing to do would be to change the path of the children linked meshes so that they show the old meshes images, and replace the old meshes with the new linked meshes inside their skin placeholders.
Does this match your situation?
But you wrote:
All the attachments are grouped in the same skin.
You can't have more than one linked mesh of the same element in the same skin visible at the same time. They are meant to be used across different skins. If you activate one and it is in the same slot of the other linked mesh, then the other can only be visible if you turn off the first.
If at the beginning of the animation you set visible the second one, you should be able to see it.
If this is neither the case,
Could I see the structure please?