Using rigify for the Unreal Engine 4?

Hi there, (warning and apology : my english is not so good)

I also posted this on the UE4 forum, but I would also would love to get your opinion:

Using Blender 2.79 and the UE4 version 4.21.2, I’m having some problems with using the rigify add-on for rigging my Skeletal Mesh.
Importing the SM itself and the animations to UE4 works fine.
When rigging the eyes it gets problematic.

After parenting the body and the eyes to the generated rig the eyes get deformed. Unparenting the eyes from the rig and
parenting them to the ORG-Bones solved the problem inside Blender.
If anyone else is having this problem, here are two posts that I found helpful:…-rigify/666202

But then the next problem occurred:
When exporting the Skeletal Mesh from Blender to the UE4 I have to make sure that the “Only Deform Bones” -option is unchecked. Otherwise the eyes wont get
exported at all.
Inside the UE4, when the characters walk, the eyes don’t follow the mesh.
And since I want to be able to control the eyes at runtime just spawning the eyes and attach them to the body wont work for me…

Unchecking both - the “Only Deform Bones” and “Add leaf bones” -option still imports a lot of bones, so this “eye”-problem lead to another, more general problem:

Are these tons of bones bad for the performance or do they make any other problems ? I want to do ragdolls. Would all these extra bones be
problematic to accomplish that ? Or does it nothing have to do with it? (I never know which bone to choose for creating a body.)

And I would also need facial expressions:

Does anyone have some experience with the facial bones from the rigify version? Is it a good idea to use it or should I use shape keys (what about performance) ? And if using shape keys: Would I still need for example a bone for the left and the right side of the face to handle hit events on the face?

Concerning facial expressions: It is for a 3D shooter where the enemies sometimes say some short sentences (when having a conversation or see the player) and for cutscenes.

Or should I forget the rigify-method and try to make an entirely own rig and keep the hierarchy like the one from the mannequin (and add some bones for the eyes) ?

These are a lot of questions…but I can not find any tutorials that handle these topics. All the tutorials that I found never explain how to handle eyes or facial expressions (for creating a skeletal mesh in Blender and using it for the UE4).

have you solved it ? I am this week finishing my skinning process, I hope works in ue4

Except for the eyes and the huge amount of bones rigify works fine and also gets exported and imported into the UE4 very well.

What also helped me:

But this is an older version of the meta rig and eyes are not discussed.