Yeah, it was a bit of a twist to have one of the thoughtless sisters turn out to be far less shallow (heh) and materialistic than as was depicted in the movie.
I'm choosing to believe that their drinks are a different consistency than the water around them which allows them to act like normal drinks would above water. This is something I tell myself so I can feel sane and unbothered while I'm jacking off.
Are her male friends on page 13 just male Belle and Aladdin?