Polly is one that I've been agonizing over for weeks now. I love the vintage feel of
Polly, but I can't bring myself to really love
Mary. I've finally decided that
Polly would make a fine nickname for
Olympia, so, I'm happy.
I also quite like
Nancy, but I can't work up enough love for
Anne.
I'm sure that these have been suggested, but have you thought about
Benedict or
Davis for your
Benny and
Davy troubles? Also, I'm quite fond of
Benny as a nickname for Benjamina...