Yep, I got the PM to open up the privacy level again, and I managed to switch another of the children, but as soon as I did, it locked the parents yet again. So I still can't switch the others.
Without adding me as a co-PM (which I don't think he understands, because he added me as a PM of his own profile), it appears he's the only one who will be able to fix this error.
I've sent him a message trying to explain what needs to be corrected.