Hi there,
1. The image is a background image, so it will only show what’s possible in the space that’s available. For example, if you want to show more of the image width-wise, the height will need to reduce, and it will cause a white space below the image.
2. Did you fix this issue? I’m not seeing it. If not, is there a specific page I should be looking at?
3. I’m not too sure what you mean. Are you wanting the posts to be wider on tablet? If so, would forcing them to be full width work?
Let me know 🙂