How do you link in the CG Cookie Flex Rig into Blender 2.8+?

I am working my way through the Character Animation Toolkit tutorial and am trying to figure out how to link in the CG Cookie Flex Rig in Blender 2.8. Near the end of this video they are linking in the rig from another file in a pre-Blender 2.8 version.

I have been able to successfully link in my own Rigify-based characters in Blender 2.8+, but things don't appear to work as they should when using the .blend file supplied for the CG Cookie Flex Rig. I can't determine if it's not working because the file I'm trying to link in was created in a pre-2.8 Blender version or if there's something that I'm doing wrong.

Here are the steps I took to import the rig:

1) The tutorial says to change the group names `cookieFlexRig` and `cookieFlexRig.lowRes` so that `cookieFlexRig` is the name of your character:

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Because the concept of groups has disappeared with Blender 2.8 and collections are now in its place, there is no UI like this in Blender 2.8 when you go to the Object Properties tab. I wonder if the change from groups to collections is the root of the problem that I'm seeing.

Interestingly, I can see `cookieFlexRig` and `cookieFlexRig.lowRes` as collections when I try to link them in from another file:

See image here

However, when I have the original rig file open, I was not able to find them in the Outliner when set to View Layer -- which is normally where I would expect to see collections:

See image here

Instead, I can see `cookieFlexRig` and `cookieFlexRig.lowRes` if I change the Outliner to Data API view:

See image here

Anyway, I didn't change the name of the `cookieFlexRig` and `cookieFlexRig.lowRes` groups in the Data API view, because I wasn't sure that might break some sort of internal reference, so I left those as-is.

2) After saving the original rig file, I created a new Blender file and linked in the `cookieFlexRig` collection. (I'm not bothering with the `cookieFlexRig.lowRes` collection at the moment, though I have tried linking in that too and have had no luck.)

3) I linked in the `Text\rig_ui_panels.py` element from the original file, which is required for importing Rigify rigs -- and appears to be required for the CG Cookie Flex Rig as well.

4) I selected `cookieFlexRig` in the Outliner and in the 3D View menu went to Object → Relations → Make Library Override…

5) I picked `rig` from the popup, since that's the name of the rig that `cookieFlexRig` uses behind the scenes.

6) I went to the script editor and ran the linked Python file, `rig_ui_panels.py`

Normally, when I take these steps with a Rigify rig I've created, I now can select the `rig` armature, switch to Pose Mode, and start posing the character. In this case, though, I just get a weird state that doesn't allow me to pose the character:

See image here

There is a collection called `cookieFlexRig` that is disabled. I'm not sure why. Inside that collection is a `rig` armature -- which is also disabled. I am unable to go into Pose Mode when I select either of these things in the Outliner.

Any idea on what's going on?