Google will typically ignore empty header tags. Google has also confirmed or has been cited as saying that using multiple header tags or H1s is completely fine and will not impact, help or hurt, how you rank.
As long as one tag is empty you will only have one h1 tag and this is fine. 2 h1 tags will only confuse the search engines.
But the title is the title and h1 is h1. So don't use h1 as page title, for title use title tag.
Old question but must be answered completely. It's very disappointing that it has not been answered in almost a year!
Those images come from either your:
Twitter card image or
Facebook opengraph image
I am not 100% from which one, but I am 100% it is from one of the two, or at least the first image that Google finds while reading your page. So keep this in ...
Google has often said that proper HTML formatting and semantic tagging is important in how they understand content on a page. They often use this in order to extract and understand the important parts of a page. headings tags like H1s and H2s are still important. Google goes to great length to identify which parts of the page are "primary" content ...
Not a Django user but I guess you will have to install a different WYSIWYG Editor from the Package list
Some of them have the HTML content editable feature you are looking for.