Go to Appearance > Widgets > either change the content in existing custom areas and then use them in prefooter or create new custom widget areas, add product widgets and choose necessary product types.
Check the screenshot http://prntscr.com/dlqd8k
I am still lost with this. If I use your example, I would first create the Pre Footer Static Block using Widgetized Sidebar and then have to also add the WooCommerce Products widget but the only options for that are to Show All Products, Featured Products, On Sale Products and then it shows the block below everything isntead of showing 4 columns.
How can I can I show 4 columns Latest Products, Best Selling Products, Featured Products, Top Rated
You need to create a row with Visual Composer and divide it into 4 columns with Widgetized areas. Then you are able to add WooCommerce Products widget in different configuration and sort products in different orders like price, number of sales or random.