Thanks for the feedback, Franck.
If you have external objects which you use as “Target”, go to the Advanced Tab of the PoseMorph, while in Edit mode, and there you find your “link-field” to (re) place the objects. I was not certain if you have had created all your “morphs” on the Spline itself, or what else was the set up. (Example files support the communication here tremendously. ;o)
From the help-manual:
Destination
Here you can Drag & drop the object which should be affected by the Pose Morph tag. This feature allows you to move the Pose Morph tag freely in your hierarchy so you can have better access to it when animating (place the Pose Morph tag on a “morphs” Null object, for example). If Hierarchies are activated, just drag the Parent object in the Destination slot. Note that objects can still be edited when the Pose Morph tag is used that way. Simply select your morph target and edit the linked object.
This option allows to use the tag on any Object, without having this object the one which will be morphed. With the list below you can stop for example that hierarchically objects might be affected.
Let me share some other thoughts here, if you don’t mind. You can set names to pretty much anything that is in the Object-Manager (OM). If you name all these—even deep down in the hierarchy—objects (here the spline) with additional “codes”, such as “abc”, or “want to see now”, “5208”, what ever, you can open a second OM and use the magnifying-icon to search for exactly those. In the appearing list will be only objects with, e.g., “5208” in the list. So you could just click in the + sign of the OM1 and get a new one. Use the search and done. OR: use the any OM with the Bookmark options. There are more options, but these seem to be the best fit from my point of view.
If that is established, perhaps set the parameters of the Tag in question as HUD (when active), and with a click on the icon (Pose Morph) in the OM you get all the parameters wanted in that moment on the screen.
I hope that helps a little bit to streamline your work. I certainly believe that you know all of that, but in my experience, they are sometimes ignored—even they save a lot of time.
All the best
Sassi