Still waiting for something as basic as group tabs.
The current implementation in Chromium-based browsers is miles ahead of what any add-on can do in Firefox.
They need to get their shit together.
The second one, I am not sure about colour coding like that, just because I have not tried, the trees you will have, however, including sub-trees. I would bet you can get the colour coding too.
First one, no idea how you would go about that, I don’t think it’s possible, but I don’t have the top tab bar, I disabled it since i use the TST sidebar. I remember there was a tab group plugin but it placed the tabs in separate menu items with the menu in the extension area.
I've been using tree-style tabs since I've switched back to Firefox. It works really well and I've even disabled the tab-bar and am only using the side panel.