Regarding your question about the menu: Kanso has two modes – one-page and multi-page – and the menu is constructed differently depending on the mode. In the one-page mode, the primary goal of the menu is to provide a convenient scrolling interface between the sections of the long aggregate page, whilst in the multi-page mode the menu acts as a classic WordPress one. Because of that the one-page menu is automatically generated by a completely custom piece of code that does not correspond to the “Appearance -> Menus” admin interface, and does not allow for submenus and menu items that lead to other static URLs. Inserting a submenu into the one-page menu would require re-writing the code on lines 95 and 131 in the “header.php” theme file. In general, I would imho not advise adding a sub-menu in this case since it may negatively impact its usability.
Sincerely,
Andrii / Satori Studio