Broken IK when generating control rig with Blender addon

Hey, been using Mixamo for a while already and was really happy to see the add-on announcement for Blender. However, when using it with a custom character, I can't seem to make the control rig work.

Some extra info that could provide clues maybe?

• I downloaded the rig with the skinning test animation, though I zero'd out before creating the control rig.
• I saw in another post that this could be related to a bone axis issue. I tried importing the fbx with many different bone combinations (y and -x, y and x, y and z, y and -z) but they either broke the rig more or looked the same. Automatic bone orientation didn't work either

As an extra, I'm curious if anyone knows if there's been any issues when exporting this to game engines? I know exporting from Mixamo straight to an engine like Unity tends to work fine, but I don't know if the new control rig may introduce mechanics that might make exporting to game engines problematic.

Thanks!