Hi,
As far as I know, one API token can be used on multiple websites, but you might need to check that with Envato (try it first).
I don’t know of the top of my head the colors and their style names, considering that there are so many different ‘styles’ for the widgets display, and from your screenshot I don’t know which one you use.
But, this is basic CSS, and you can find out names of the classes used for any element using Chrome or Firefox debugger, and create new styles to override. Any extra styles you create should go into your theme style.css file.
Regards,
Milan