Am animation student - across Disney there are many different animators with different styles that, while come together to make a "Disney" film, they all have their own techniques and tendencies (ex. if you know who Glen Keane is, you can easily tell when he was the concept artist/animator for a film... Tarzan, The Little Mermaid, and Pocahontas, all Keane films, for example, are very different from Walt's animated films, including Snow White and Cinderella.) So that's really why "Disney" is just too broad a style. It would be like saying "Final Fantasy!" Which Final Fantasy? Yoshitaka Amano, who did the first 6 games, or Tetsuya Nomura, who's done almost every major FF title since 7? And even then, Amano still does FF art, he's just not as integral a part of the designing team, so you'd still have to differentiate.
If we did follow the lines of Disney, I'd love to see you guys try your hand at some Glen Keane. He draws some pretty awesome ladies, and he's got tons of references, concept art, and animation reels you can find online.
Or just did what OP suggested and pick a specific movie and go from there (so like, "draw something in the style of Treasure Planet!")
Otherwise, I vote for the 50's style one! <3
also @El_Psy_Congroo, here's mine! kawaii as fuck