That's step 2>>94292452>title card
I don't remember that, but she was in the background with Ice King's princess collection at least twice, one of which was in his imagination and one was princesses he actually had collected in one place.
So you're right, she was never as major a character as HW, but I deny that she was never as big with the fans. The two of them had equal amounts of fanart (impossible to prove now since obviously since her episode HW's has exploded), and often the two of them together.
Let's put it this way, Jungle P was definitely ahead of Lizard P in terms of fan desire for apeparance, and Lizzy actually appeared... very briefly, no dialogue, just smooched Finn, but still.