Arabasta for some reason has a poneglyph even though they were part of the 20 kingdoms that fought against the ancient civilization that had them built, and now we know the ruler of the time was a woman that vanished for not going to Mary geiose, and on top of all that Imu seems to be pensative about Lily and has a interest on Vivi. Its not much of a leap to think she ended up becoming a friend or even lover to joyboy at some point during the war and Vivi and Luffy are basically the second coming of those 2