Ah-ha! So that's the reason for Berry. Makes sense - I was mildly puzzled by American posters saying they wouldn't use Barry or Harry because they disliked Beary and Hairy until I said it out loud in my attempt at an American accent; and this must be .
I agree that Cheryl and Cherie have got nothing to do with Cherry from a scholarly perspective, but the looks and sounds are so close that I'd be surprised if Cherry didn't get used as a nn for Cheryl especially. But there isn't an oversupply of Cheryls right now. Interesting that Cherry predates the others.