I have always thought that
Petunia was a beautiful name for a girl, and never understood why it's uncommon. When I was a little boy, I used to really like horses; I told myself that I'd get a white, thoroughbred mare and name her
Petunia (lol, that has never happened). I think that
Petunia would be a fun name for an animal to have, just as a human girl. Anyways, I really love all of your name combinations;
Petunia Rachel is my favorite, however.