@hk995 Please vote for the existing feature request.
Option to Autohide Tab Bar UI
As a workaround for now, shortcuts can be assigned to show/hide toolbars. They work in fullscreen mode.
0_1539804857151_Fullscreen Tabs.png
0_1539804864493_Fullscreen Address Bar.png
If you add this link as a web panel you can easily search for other feature requests simply by changing the search string from "Autohide" to any other term. Enclose more than one word in quotes to search for a precise phrase.
The second request is a bug rather than a feature request. It has been around forever and is mentioned from time to time.