Try the following to export the fbx.
1 -Choose the blueprint you want to export (face or body) on the content browser, right click and Asset Action> Export
2 -Export it to the same folder where the uasset of the blueprint is located (Content>SampleMetahumans>…)
3 -Choose FBX ASCII, uncheck everything except the morph target (but you can uncheck that too, but there will be no blendshapes).
4 - The Unreal will alert that there is a new asset, try to import. It will fail. Open the same blueprint that you exported and on the mesh tab, click Reimport base Mesh> Reimport Content>Geometry. Choose the fbx file that you exported on step 2
5 - Now, right click again and export it to fbx, the same config from step 2, to a different file. This FBX should be imported correctly in Maya (if there are blendshapes, it may take a while. So first try unchecking this option)
What I noticed is that when you first export the fbx, there are no source files associated with the blueprint. After the reimport content>geometry, it will associate the fbx file to both the Skin and geometry. (you can check this option by just passing the mouse over the blueprint so it shows the infos)
I can attach pictures if you cant make it.
The control rig I didnt manage to export. Don’t know how to do it. But the fbx comes with all the joints and the mesh skinned