The hair strands are waaaaay too thick in the last example. Try scaling the textures in the x axis, by as much as 50%. Your hair is also dead, no specularity or gloss to be seen.
Not really possible to say when looking at padded textures. If this needs to go into Unreal then it will need to be adjusted with that engine in mind and on the model. Btw. the jagged look I was talking about is not in regards to geometry - different issue - but rather bake output quality. You have no antialiasing going on…