Rated 4 out of 5 stars

This is good.
However, I want to display tab bar to the right of the folder pane and display always folder pane, if possible.

This review is for a previous version of the add-on (1.0.0.0). 

Not what this extension is ment to do

In theory the behaviour you describe is possible. However, it has a very high risk of breaking something, as it would need to move MANY things around:
1. the toolbar above the tabbar, just like rise of the tools.
2. the tabbar into a new container, which also includes the content switched with the tab
3. the folder pane into the parent of this new container

Even this add-on did not get a full review here, with a smaller risk of breaking something. So I personally don't think this is possible with keeping Thunderbird staying stable, as there are various add-on combinations possible.

However, a dirty implementation without cleanuping when disabling, etc. should be easy to do, if you really want this write me an eMail - but I won't try to submit that as public add-on.