KatrinaB This is a really great question. If you have access to Vocalize (CX Dashboards) you can aggregate the questions that are the same any way that you like--showing an ongoing trend over time or segmenting them based on other characteristics.
You can also show period on period changes: InessaG recently posted a great tactic to use in dashboards to accomplish this.
For the questions that change, it would be very interesting to show those in a dashboard as well and also use those to filter the data that is consistent from month to month.
You can take a similar approach in StatsIQ to segment the consistent data and also filter it by the monthly questions.
I hope this is helpful! Please reach out if you'd like to discuss more...