Thanks everyone for helping identify these.
From top to bottom:
(1) DSC (could only toggle on/off for E9x M3, now can select MDM mode as well)
(2) Throttle mapping (equivalent to "Power" button for E9x M3)
(3) Adaptive M Suspension (equivalent to "EDC" button for E9x M3) (optional)
(4) Steering Weight (only changeable via M Drive for E9x M3, now gets its own button)
(5) Sideview cameras (optional)
(6) PDC on/off (optional)
(above quoted and modified from southlight's summarization)
And the button on the chrome shifter surround controls the DCT shift program (Drivelogic).
With Adaptive M Suspension:
Without Adaptive M Suspension:
F30 for comparison, showing DDC switch instead of M DDC buttons:
