So bias of me :p but all of them deserve it imo.

All of them, but Belle and Mulan especially and Ariel to a lesser extent.

Mulan or Elsa.

All of them but Elsa, don't get me wrong ,I love Elsa, but I think she's overrated

She is NOT overrated and very original

Um...I will think everyone of them deserve it .but idk why I think that.

Also Rapunzel and Anna.

All deserve some praise, but at some points Belle, Ariel, and Elsa get overrated.

*Sigh* She is my least favorite, but she deserves praise. Also Rapunzel, because she's optimistic, caring and intelligent.

Really, I would say Mulan, Belle, and Ariel (and all the Renaissance princesses, for that matter) have lost quite a bit of popularity.
She sacrificed everything she had to protect the ones she loved.

Mulan and Belle, I suppose. All of their praise seems pretty well deserved in my opinion.