Is it possible to have the filter widgets appear above the listings instead of below when viewing on mobile?

This is a function of your theme and how it handles the sidebar when it collapses into a mobile view. It is not currently possible, though Sabai intends to enhance this functionality:

“What we plan to do is to hide the filter form widget on mobile devices and instead show the filter form above the main content section of the page, similar to how it works when you toggle the fullscreen mode of the map.”