Hi @dcngibson,
Thanks for contacting me here.
Answers below:
1) Font and colors are controlled with CSS. To change this, you’ll want to create a custom CSS file and add the right selectors there. Here is an article about how to use custom CSS with Business Directory in a way that doesn’t get overwritten on upgrade of BD: http://businessdirectoryplugin.com/support-forum/faq/how-to-use-custom-styles-with-bd-2-1/
2) Image thumbnails are controlled via our image settings under Directory Admin->Appearance->Images tab, look for the Thumbnails section. Here’s the docs on that: https://businessdirectoryplugin.com/knowledge-base/appearance-tab/#image
Remember that once you change these settings, you’ll need to re-upload the images again to get them to resize. They don’t do this automatically (for performance and image quality reasons)
3) Right now, we don’t have an easy way to support that. The featured image badge is intended to be separate from the other images as a marker that the listing is special. That’s something we can consider adding in the future, but it’s not available today.
I hope that helps.
Please let me know if you have any other questions or issues!