I use Blender with UE4, I usually assume that exporting issues have to do with the way the thing is setup rather than the programs themselves. In the case of .fbx, the SDK is proprietary and owned by Autodesk, which makes it difficult for Open Source to use as they tend to be shuttered by beaurocracy. Believe me, if they were allowed to properly integrate it, they would. But I guess that’s life.
Yeah, it’s annoying having to figure out stuff like this, it should just be straightforward, but it’s par for the course in dealing with free stuff, even if Blender and Unreal are both most excellent pieces of free software. Unreal being just a bit more expensive than free.
When dealing with something like a Blender export, there’s usually a standardisation process that needs to be followed to make sure that Blender’s info is compliant with UE4’s import info.
Also, if you want to scale the model properly. The export options has a little scale option, it’s default to 1 unit, which is 1 unreal unit. So you’ll need to set that to something like 50 or 100 to make it more realistic in size. That should solve any size issues without having to manually scale the mesh or bones.
I know it’s annoying… but hey, you get to make the first export/import animation video for Blender to Unreal if you succeed. Free hits!