Multiple Company Selection in Different Slicers

Please try these steps for the first part of your question and let me know if it still does not work. Also, make sure to keep a backup of your file.

I created it this way:

Step: Please check whether your model is similar to this.

Next step is to do bookmarks, as you already have everything:

 and for each of these set the show hide accordingly. Say, like these for the 1, 2, 3 ... 

, , 

Go through each bookmark, right click, uncheck the data:

You can give bookmark names of your choice. 

Test: click on these buttons after configuring the actions and they should work.

All three should work i.e., based on the (black) buttons, the charts display accordingly. 

------- by now all 3 bookmarks functionality should be working -------------------

Let’s look at the slicers next.

• From the 3rd page, which is the dashboard, select the first slicer that is linked to the Comparison1 table column. Give it a name so we can reference it later. Copy it.
• Go to page 2 and page 1, paste it. This will ask you whether you want to sync slicers or not. Say yes.
• Select the slicer using the Description Table in Page 1. In the sync slicers, in the advanced options, use the slicer name used for the first slicer in the 3rd page. Similarly, do the same step in Page 2.
• Now, hide this newly copied slicer in page 2 and page 1.
• It should work. Please check this video, and this is what you need in my view.

https://www.youtube.com/watch?v=jKOjXPkXO8U