Hi There,
If you have a log that fits your desktop but not your mobile, you can actually add two logo images.
On the customize tab of each bar, container, and elements, including the image element on the header builder you will find a Customize tab, on the customize tab you can hide the element based on screen size, that way you can display one logo for desktop and another for mobile.
On the header builder, the inline menu element and the mobile menu elements are independent differently from X where it converts automatic, that is done in order to offer you limitless flexibility.
When you set your inline menu, you selected your own menu to replace the sample menu. Same has to be done with the mobile menu. To visualize your mobile menu, click on the mobile icon on the very left tab. The different screen views will drop on top, select the mobile. Click on the mobile icon. On the settings you will find the option to choose your own menu and replace the sample menu.
Hope it helps