hello,
not sure I understand the problem but I struggled with joint times ago (can be inaccurate).
1 :
position of the joint itself define the pivot center of rotation, you have to place it where it need to be
if I remember well the "pivoted" objects will be "attached/bonded" to the pivot by there origin.
at last, pivot node itself should not be a child of neither of the 2 rigid bodies (ex: on the same "level")
in general consider the joint as an object itself which has constraint with 2 others
(both bonded objects have equal relationship with joint, it is not one attached to the other one, it is both attached to joint)
2 :
translation : to place the center pivot
orientation : you will may want to block, hinder some axes so orientation will matter
scale : I don t even want to know what it does