When you have a character finished with the parent-child relationships, do not change anything in the hierarchy for the different poses.
Once you have the character finished and the hierarchies established in all the branches, you should maintain this structure for all the animation keys that you create. If you change the parent-child relationships or the directions of the branches, this can cause the entire character to break, and the behavior of how objects should follow each other can be unpredictable when changing parent-child relationships in the middle of animation keys.
In summary, make sure you have the hierarchies you want before starting to position and create animation keys, and maintain that same structure throughout all the poses you create.
