Since I got asked about the hamburger for the quick menu buttons, I'm sharing my code here. As it's not so long ago that I've started learning Ren'Py, I can't guarantee that it is the best way to implement this. I mainly pieced it together from different topics on Ren'Py forums on how to implement a GUI with extra screen popping out. The logic can be used for any type of screen element.

The edits are done in screens.rpy, and mainly consist of four parts:

[1] Add boolean variable to remember the state of the hamburger (whether it is open or closed). Do this at the start of script.

[2] Editing the existing screen quick_menu()

[3] Add a new screen with the content in the hamburger, in this case: the quick buttons. I called this screen quick_buttons().

[4] style definitions for the buttons