Notes on UE4-Blender workflow

In UE4:

When you import a rigged model (mesh parents armature) to UE4, it will be converted to a Skeletal mesh, a skeleton and a physics asset

 

An animated FBX will be converted to the 3 files mentioned above and anim sequence.

(You simply export the entire animation from blender into UE4, now UE4 will have an import dialog where you can specify the start/end range)

Blender Animation keys might be off

So you do not need to reimport the skeleton every time you want to create a new animation. You specify what skeleton you want to use, and UE4 will retarget the imported FBX animation onto the skeleton

In Blender:

Only select the object you want to export

re-target the anim and
remove the duplicates later.

set the scale to centimeter

You can always reset the axis in the export tab, UE4 uses the classic Pitch/Roll/Yaw, Unity uses CG way(Y: vertical, Z:depth, X:horizantal)