Nobody seems to realize that Daisy was created in a freak accident. Gunpei Yokoi named the Princess Daisy in SML even though it was intended to be Peach. She didn't become her own unique character until Mario Tennis 64, when the folks at Camelot Software Planning thought Luigi needed a doubles partner. As for "Daisy" appearing in the movie, well that was a mistake on part of the director, because around that time the Princess was never referred to as Peach, only Princess Toadstool. Guess they played SML and assumed that was "Toadstool"'s first name.