The Order of Rig Elements
The rig element hierarchy can (and in some cases, should) be different from the joint hierarchy!
When you create proto elements, the ones you add before become parents for those you’d add later. Therefore, elements should be added consequently, from the pelvis to the head, and only then limbs should be added.
If your character has a huge number of small joints, creating rig elements for every one of them is not necessary. Instead, you can create one set of elements for several joints (see Rigging Complex Skeletons).