There isn't a new mobile theme. If you're referring to the new slideout menus, they are still in testing.
There isn't chat Icon in his screen shot!
Last time I needed to make some simple changes to Lavender, I did so by just forking it and adding my changes to it, without touching Vanilla.
Now I am trying to start a new theme that would be more suitable for use as a support system, and I think I am going to add a bit more changes. For example, I like to modify what gets displayed in the header menu.
If I only fork Lavender I wont be able to make any changes to
menu.tpl since that is coming from its dependency which is the Vanilla theme. How do you think I should go about doing this? Should I copy the content of Vanilla theme into Lavender and continue, or is there a better way of doing this?