After many month I did it: I made a photo (okay, two photos...)!
That is how it should be and
then sometimes without anybody doing anything strange:
P2 and P3 switched (now even with P4 switching lol). And we still don't know how that happens. However, we found out that it will go back to normal without doing anything at all. When I tried to make a photo we used the menu to halt the fight and I wasn't the fastest... it switched back to normal again while we were still in the menu.