For me, the control button doesn't smooth the snapping, but pivots the node instead. The snapping tool is now two separate buttons also, the smart snap and grid snap.
As for the icons, I have dragged and dropped the .svg paths next to the class names and saved, but the icons haven't changed.
Indeed, ctrl now rotates a node. You can find an updated set of shortcuts here:
https://docs.godotengine.org/en/3.5/tutorials/editor/default_key_mapping.html
The equivalent of snap is the "grid snap" as you guessed.