3) We have fixed the number of the product categories per row. Check, please.
1), 2), 4). Are you just resizing the browser window or checking on the real device? Because if you resize the window then you need to reload the page after resize, the script that makes the sidebar sticky need to update values to set correct parameters and it happens during loading page. So, either check the page on the real device or refresh the page after resize. Or disable sticky sidebar option in Theme Options > E-Commerce > Product Page Layout.