and how about a conclusion to this thread,
the apple camera adaptor works 100% with my zoom h6.
i can use any input, combinations of mic/input, etc. there are no issues.
if the irig worked it would have been a bit more convenient, but then again the zoom has great built in mics so that's worth the extra work.
Great that it works for you. Just in case you want to use the H6 as a multiple-input interface, then you have to change the set-up in the menue system. Now you are using it as a stereo-sum interface. This is the reason it works as you want it to when using it with - for example - the camera-app.