Tableau can connect to DB2 z/OS series.
Not a 100% sure if it can connect to the specific file types that are specified but I would connect and try it out!
don't know whether you are still in charge regarding mainframe. Please have a look to my idea called this idea. Maybe you like to vote and share as well in your community.
"Data Source connectors for various IBM z/OS (Mainframe) based data formats"
You can find it when searching the forums for tag "mainframe".