Using custom transformation orientations in rigging So, I have a robot that I am rigging (think eve from the pixar film Walle). It's shaped like a large diamond. https://ibb.co/cSCOPb. But the four bottom panels open up so that it looks like this: https://ibb.co/bHzRcw. The way that I am currently doing it feels really janky. Since I want to rotate the panels along an axis that isn't solely x, y, or z... I've created my own custom transform orientations. 

This might be a side-problem, but I can't really rotate using the transform manipulators. It works fine for scale and position, but anytime I click on them to rotate it just moves the 3D cursor instead. I can find one or two tiny and specific spots that allow me to rotate using the manipulators.

And I haven't found anything that adresses using the lock axis hotkeys for custom orientations...

Furthermore, I'm trying to translate all of this into a rig. Since the panels only ever need to go from rotation A to B or in the middle, it'd be great if I could just create a rig that limits the rotation to those values, but I'm having a hard time figuring out the rig constraints to do that...

So.... Overall question is: Can I rotate on my custom axies using axis lock hotkeys?

Follow up questions are: Is there a better way than that? And can I create a rig that essentially does it for me?
That's exactly what a simple single bone does: it rotates in its own (local) axis, so that its rotation world is affected by its rotation set in edit mode.

If you really need (and I don't think so) the triangle of bones following the panel, you can parent them to a bone set as in my example and use it as the main rotation bone.