Personalization of clean magazine

Hello, Can I put an image on the top of the home page and the menu on like this blog ? : http://oiseaurose.com/ Can I organize the home page differently, I mean, put others texts than articles in the home page like again this blog ? : http://oiseaurose.com/ Is it difficult ? Cause it is my first blog... The menu can be fix when I scroll to be visible always ? Can I put a grid of pictures from Instagram down to the page, horizontally ? Can I have the sidebar at the beginning of the home page and then, at the end, be full-width without the sidebar ? Can I change the color of the menu and frame ? Can I post videos ? Can I add a gallery ? What plug-in are compatibles with this theme ? Is the dummy content included ? For the paying formule, how long time last the support ? Thanks a lot for your fast answer !