I will make few screenshots of the Interface lines, with all examples1-6 or other/newer on monday.Regarding the oszilloscope
Have you also tried examples 4 and 6 yet?
#include "input_i2s2_16bit.h"
#include "async_input.h"
...
AsyncAudioInput<AsyncAudioInputI2S2_16bitslave> i2sSlaveInput;
AudioConnection patchCord1(i2sSlaveInput, 0, XXX, 0);
AudioConnection patchCord2(i2sSlaveInput, 1, XXX, 1);