Thank you so much for your questions.
1. Placeholder for logo and Advertisement ? You will find all the options related to menus are on Appearance > Customize > Site Identity and Advertisement options are inside Appearance > Customize > Header Options > Header Advertisement. Please use the options available there.
2. You can change the menus fonts from Appearance > Customize > Layout/Design Options > Font Options. You will get more that 100 fonts family, use the necessary fonts from the dropdown.