Okay, I've got the Konima code working!

I switched the controller mode for the SF30 Pro to "Android Mode" to get the triggers to recognize in the configure input menu. Thanks @Rion for pointing me back to that thread.

I paired the controllers again in the bluetooth section of retropie-setup.sh, and went through the configure input process in ES a couple of times just to be sure.

I am seeing the es_log file being written to now! Something I want to make clear is for anyone else testing is that inputs are only logged while in a core/system menu, and not while the ES Menu is displayed. This also means that the passkey (Konami code) can only be entered while the gamelist is visible (not the ES UI menu).

Here's my output which also answers my question about isValidInput... it's yes when the button press or keydown event is true and no when the keyup event is true.

lvl2: EmulationStation - v2.7.3rp, built Jan 7 2018 - 04:49:16 lvl2: Creating surface... lvl2: Created window successfully. lvl2: Added known joystick 8Bitdo SN30 Pro (instance ID: 0, device index: 0) lvl3: SystemView::getViewElements() lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 up, isMappedTo= up, , value=1, isValidInput: yes lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 neutral?, isMappedTo= down, left, right, up, , value=0, isValidInput: no lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 up, isMappedTo= up, , value=1, isValidInput: yes lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 neutral?, isMappedTo= down, left, right, up, , value=0, isValidInput: no lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 down, isMappedTo= down, , value=4, isValidInput: yes lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 neutral?, isMappedTo= down, left, right, up, , value=0, isValidInput: no lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 down, isMappedTo= down, , value=4, isValidInput: yes lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 neutral?, isMappedTo= down, left, right, up, , value=0, isValidInput: no lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 left, isMappedTo= left, , value=8, isValidInput: yes lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 neutral?, isMappedTo= down, left, right, up, , value=0, isValidInput: no lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 right, isMappedTo= right, , value=2, isValidInput: yes lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 neutral?, isMappedTo= down, left, right, up, , value=0, isValidInput: no lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 left, isMappedTo= left, , value=8, isValidInput: yes lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 neutral?, isMappedTo= down, left, right, up, , value=0, isValidInput: no lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 right, isMappedTo= right, , value=2, isValidInput: yes lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Hat 0 neutral?, isMappedTo= down, left, right, up, , value=0, isValidInput: no lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Button 1, isMappedTo= b, , value=1, isValidInput: yes lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Button 1, isMappedTo= b, , value=0, isValidInput: no lvl3: UIModeController::logInput( 8Bitdo SN30 Pro ):Button 0, isMappedTo= a, , value=1, isValidInput: yes lvl3: UIModeController::listen(): Passkey sequence completed, switching UIMode to full