1. No content will show up on the page set as the posts page – WordPress ignores it.
2. That’s correct, the Blog Page Header will only appear on your posts page.
3. If you set the image as a background and add content, the content container will only be as tall as the content. You can add padding to the top/bottom of the area to reveal more of the background image.
4. Thanks for pointing this out – bug fixed.
5. There’s a text color option so you can choose a custom color. As for the font, you can do this using CSS if need be (loading a huge dropdown with all Google Fonts takes up a lot of resources).
Thanks!