You shot the first image at f/5.6. That gives you a fairly shallow depth of field. With that aperture, the bridge will necessarily be blurry if the leaves in the foreground are sharp. Even with a smaller aperture, this will be a problem, but less so. I would shoot this with a small aperture, perhaps f/13, and focus as close as you can without making the bridge out of focus.
In my opinion, of pictures 2-4, #2 is by far the best composition. I think it is a very good image. The path draws the viewer into the scene. However, the area under the trees is too dark. I would lighten it and then add back some contrast if needed. I would also do some local adjustments, but just making those global adjustments got me this image. I might have overdone it, but you can see whether brightening this area would help.