Are you adding the character via the “Add Character for Animation” tool? If not, you’re probably opening the file, which means there won’t be a namespace for the UI to operate on.
The other problem could be the character has no thumbnail icons for some reason. This can happen if you made the rig on a different machine or someone else made it and didn’t supply the icons for you.
is it possible to have IK/FK control with out the animation interface menu?
yep! there is a node called “Rig_Settings” pretty near the top of the rig hierarchy in the outliner.