I’m just re-writing some of your instructions as they were missing a couple of steps that was confusing me as a beginner:
Makehuman -> Blender -> UE4. That would be:
*) Export from Makehuman as Collada (dae) format and Scale Units set to “centimeter”. With “Game engine” skeleton.
*) In Blender ensure your Frame Rate is set to 30, Scene units set to Metric, with Unit Scale 0.01.
*) Import into Blender with “Fix Leaf Bones”, “Find Bone Chains” and “Auto Connect” selected under Armature Options.
*) Import the UE4 mannequin into Blender (This is your exported UE4 SK Mannequin that has been exported as FBX from Unreal Engine).
*) Put your camera in Front Ortho view. Resize the UE4 mannequin mesh with your Pivot Point tool set to 3D Cursor and then by pressing “S”.
*) Pose the Makehuman character to get a (very) similar pose to the UE4 mannequin. To do this: In Pose Mode select the individual bone joints and move them using the arrows so that they closely match the layout of the UE4 Mannequin. (afterwards delete the UE4 mannequin)
*) Apply the armature modifier to all of your meshes. To do this click on your character in the Outliner. Expand down, and beside each of your Meshes click the wrench icon. Then click “Apply”.
*) Apply the pose as new rest pose in pose mode to the skeleton. Select your character and choose “Pose Mode”. On the bottom left Blender menu click “Pose” -> “Apply” -> “Apply Pose as Rest Pose”
*) Add armature modifiers back to the meshes. To do this select your character in the Outliner. Expand to your meshes. Click the wrench icon. Click “Add Modifier” and select “Armature”. Set the Object as your characters Armature. (Don’t click Apply).
*) Add twist bones (they are a must have). Copy vertex groups (e.g. upperarm_l) and split the weight up (autonormalizing on and subtract and blur) between the twist and the normal bone. (Not sure the exact steps on this but needs further documentation).
*) If you like you could add some IK bones. They are pretty useless in UE4 (as you could use the IK functions even without them in UE4) but very handy while animating in Blender. (Should add documentation for this too for animating in Blender).