From my limited testing, I was able to get the dashboard filters/prompts to work for reports that I created while in Canvas Dashboard. If I added an existing report that was created in the standard report , the filter would not apply to that report. 

We have also struggled with the lack of notification on for approval results - specifically around when you submit an object for approval and not receiving a notification if it was approved/rejected. I created a flow in Fusion to do a tagged update to force an email. If you want to create a report o...