You can create custom toolbars and dock them next to the tool windows you want the extra controls associated with. It's a bit manual, but that's a working solution. SlickEdit never had the ability to add toolbar buttons to tool windows.
On another note, your suggestions are thoughtful and helpful, but it would be more appropriate to post feature requests to the "Features and/or Improvements" board. This board is for the SlickEdit 2017 beta, and as such, is not a long-lived discussion, so all your great suggestions will eventually be hidden away. However, the features discussion lives on forever.