If these widgets would be text widgets with content, it could be done by one text widget and using inline columns for the rest of the content you need. However, doing this would require some careful coding, otherwise the quick answer would be not possible if you need something other than text widgets. This is due to how the structure is done using the Bootstrap framework.
For that, not possible. In fact, I cannot think of any other theme that has that capability of spanning widget positions. However, you do have one option, is to use a page builder plugin like from site origin. You can create almost any kind of layout you want and would do what you want. The only problem is that this does it in the content editor for a page or post…it won’t do anything in the footer widget group. To do that, you would need t create a new template for the theme.