Merlin is most known to me and family as:
Mergits, Merly Whirls and Mr Tops - and he comes to all of them!
Oakley is generally called Okey Pokey or Fat boy - he doesn't come to fat boy but then again would you?
Thats how we chose the names for both of our boys based on the fact that you could make it rrhyme with something. The name Fat boy came about because Oakley is a mini Augustus Gloop!
Edited to add:
The two together are commonly known as the rat bags!