3. I think you will need to make some change on dimension for certain image or you can add custom css code for certain image.
4. Just want to make sure about this thing, so you want to know what kind of page template that used for each page that you’ve been created. If so you can inspect those page and find on class name on body tag. Those class name will refer to page template that used on those page.
5. It’s weird for me because i don’t have those kind of problem yet. If the problem still occurs please try to disable all plugin except the required plugin that come with themes.