How to solve Keyboard Accessibility issues?

I'm encountering a few issues with the keyboard accessibility of my Tableau dashboards: 

Tab-order issues:

1. Articles (like this one) that describe how to change the tab order of dashboard objects usually suggest assigning a very high tab order number to 'ornamental' dashboard objects that shouldn't ever receive focus. However, I've found that those objects simply end up receiving the focus after the higher priority objects do, so eventually the user will be focused on some object that's supposed to just be ornamental.  How do I take some objects out of the tab order altogether?  What does NOT work: Setting the Zone ID to 0 or a negative number in the XML file causes an error that won't allow the workbook to open in Tableau. Commenting out the zone section related to the object in the XML file removes the object from the dashboard altogether. That commented XML section is also deleted upon saving the workbook, so you'll have to recreate the dashboard item if you want to reinstate it.
2. When clicked, the Download buttons on my dashboards invoke a pop-up window, but do not return the focus to the same button after the pop-up is closed.  How do I ensure that the focus order stays intact after the button is pushed?

Tooltip issues:

1. When keyboard tabs are used to focus on a dashboard element, the tooltip associated with that element isn't triggered. That means that keyboard users lack key information that is available to mouse users. How do I display tooltip content associated with a dashboard element to a keyboard user?
2. When tooltips are triggered, they sometimes obscure other content. Is there a setting that would allow users to close tooltips by pressing the Escape key, for instance?

Page navigation:

1. I found the suggestions in this thread (Pagination of dashboard views) very helpful for implementing paged views in a dashboard. That workaround relies on using shape charts as buttons combined with dashboard actions to navigate through paged content, but I'm not sure that those dashboard actions can be triggered by a keyboard. Is there a setting I should be using that would allow keyboard users to 'Click' an embedded shape chart? Or is an alternative approach to page navigation now available?

 I'd appreciate any insights into how to address these issues. Thanks in advance!