I have just remebered the thread and found my spare buttons. The are easy to open, just a couple of clips on the sides that can be carfully bend with a small screwdriver.
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The red connectors can be pulled out. So it ist physically quite simple to combine different left and right keypads. That does not necessarily mean that they will work together.
You may try swap you right keypad (with the button for heating) for another right keypad (without the button for heating), as long as the new keypad also has the white two pin connector for connection the right paddle (alternatively you an just change the front case). Then you won't have the additional button for heating on the right keypad.
I don't think that you can swap the left buttons, because then you will be again missing the connectors for the paddles and HOD. You can of course swap the case with the buttons of the left keypad. Then you have the assistant menu button on your keypad, but unfortunately the keypad does not know that and thinks that you are pressing the travel assist button and does not know what to do. So instead of having a non funktioning travel assist button you will have a non functioning assist menu button.