Hello,
First of all thank you very much for your interest in the theme.
Regarding your query, as for the header image we can help you with the custom CSS so once you build the site using the theme then please let us know so that we can provide the CSS fix. It is same for the menu as well. Once you use the theme kindly let us know so that we can help you with the custom CSS.
Further, if you have any query/confusion then kindly let us know.
Thank you.
Best Regards!!