License and theme specific questions

Hello, already tried to reach you via email, but unfortunately didn't receive an answer yet. So I ask my questions just here: 1. If I buy Catch Responsive Pro theme, the featured license is GNU V3. Does this mean I pay one time 39,99 $ and can use the theme as often and for as many client's end products, I like to? 2. If I don't need a logo or the search bar and remove them both, is it possible to reduce or delete the Header space above the top menu, so that there is no gap with background color? Or is it possible to have a self created color in this area, not the background? 3. Is it possible to change background, hover, shadow and text colors of the mobile nav bar? 4. In original the mobile nav bar shows all menus at once, that means also the 1. and 2. level sub menus. If there are a lot menu pages, the whole mobile page is filled with the menu bar. So is it possible to hide the sub menus (show only the main menu) and let them only appear, by clicking on? Feedback would be great! Thanks!