That was just a sign that meant "Do you like to dance ? ". And when Squall saw the sign he moved his head in a way that meant " That's not a bad idea . " And Rinoa walked to him and took him to dancing . I don't think that could mean anything else .

And about R=U theory , I really don't like it because all the evidence in the game are against it ; And I could find nothing that could mean it's true . If you found something let me know too .