I was able to come up with an example of how to make the links for the dashboards to just be 'hyper links' instead of arrows. There are how-to instructions in the caption of the Attendance (2) worksheet.
Here are the written instructions on how I made the single text 'hyperlink' for the dashboard.
1. Drag the [Attendance Dashboard] pill to the text file on the 'Marks Card'
2. Right click on the header and uncheck the 'show header' option.
+ Additional Note: The buttons may have to be resized on the dashboard to make scroll bars disappear
As for the additional question on trend lines being added to the end of the text box, i do not believe this is currently built into the product and the work around that is already implemented is the best solution. There is a community forum for voting on peoples feature suggestions found here: Ideas , there you can search for an idea that is similar to this or post your own. Others will vote and it might be added to a future release of Tableau Desktop.
Text Links example.twbx 450.8 KB