You can edit Content Box for styling the box and then edit the Contact Form 7 Pro element for styling the form.
For editing the form fields, you can go to Dashboard > Contact
Instead Quick Contact also you can create any page and assign it.
You can find the Popup Modal Box element under this button in Page Builder and click on #guestbook_popup and it will open and then you can edit it and add or remove content of modal box.
This Popup Modal Box had unique id (guestbook_popup) and you should set button links to this id with # character like this: #guestbook_popup
In widgets find Footer 1 sidebar and edit it.
For changing background of Footer, Go to Theme Options > Footer > Footer Widgets > Container Style Kit