Hi Joe,
By Header, are you referring to this?: https://share.getcloudapp.com/YEukonnp
When importing Coach, it adds a Page for the homepage, and removing this imported site removes the page as well, along with all the other stuff imported.
With regards to the image, can you try re-uploading your retina logo in Appearance > Customize > Site Identity?
Kindly let us know how it goes. If you’re referring to something else with regards to the header, kindly let us know.