You can edit Carousel settings in its edit settings and change the clients Images from their edit.
Instead Quick Contact also you can create any page and assign it.
In widgets find Footer 1 sidebar area and edit it.
For changing background of Footer, Go to Theme Options > Footer > Footer Widgets > Container Style Kit
This Footer has “Fixed footer under body ?” option On, if you want to turn it Off go to Theme Options > Footer > More
For green shape go to shape tab of this element.