Thanks for looking into this Marc - nice to have another set of eyes on it.
I agree that it's possible the noise covar matrices are being used somewhere else, but maybe unlikely as the source images are (at least by-eye) identical when using different noise data.
If the noise covar isn't being used, maybe the best option would be to remove the requirement to compute noise covar before running LCMV, and then edit the tutorials to clarify?
Thanks,
Alex