Looks Like you are nearly there. Once you have a list of theSorted Viewport Types that you want to switch the Viewports to, you should get the ElementID of the Viewport types. Then you can use the Python Script in this thread and feed in the Viewports to the first port and the Viewport Type Element IDs to the second port.
Ideally you could just feed the Viewports into a SetParameterBy Name node with the parameter as “Type” and feed in the list of Viewport Types as the Value to Set, but i have found that getting “Type” from that node is not stable (it may work for 95% of a list and then miss the other 5% - run again and you will see that some that worked previously will suddenly be “null” and others that did not work now seem to work - the Python Script does not have these problems)