Belle does look into that mirror an awful lot, doesn't she? Artist Chris Hill noticed now nicely the princesses seem to match up with the Seven Deadly Sins. Ariel as Greed? Nailed it. His non-Disney Rapunzel is awesome as well.
http://creativegreed.com/inspiration/disney-character-7-deadly-sins.html via Flavorwire
Artwork isn't bad, but the theme is reaching a bit....
van·i·ty? ?/?væn?ti/ Show Spelled
[van-i-tee] Show IPA
noun, plural -ties, adjective
–noun
1. excessive pride in one's appearance, qualities, abilities, achievements, etc.;
So yeah, vanity is another way to say pride.
As for using Esmeralda for lust, that wouldn't work. It seems clear that the artist is trying to find people who embody the sins in question. Cinderella is lust because her ultimate wish was to have a handsome prince. Ariel was greed because despite all she had, she wanted more material objects. Tink was envy because she was envious of Wendy. What lust did Esmeralda have? Did she want to have sex with Frollo? No? Then she doesn't embody lust, just because someone else felt towards her.