The best Disney heroine? Without a doubt, the honor must go to Mrs. Jumbo, Dumbo's mother.
The mother is imprisoned, and her baby elephant goes to the wagon where she is being held. A short whistle, and the mother, who at first has quite possibly the saddest look drawn on any Disney character ever, lights up and runs to the window where she can see her baby's truck. But no, the master Walt doesn't allow her to get far; a heavy chain prevents her from seeing her baby. So she bravely reaches through the window, and gently caresses and eventually sways her baby to the heartbreaking tune of "Baby Mine". Just watch the myriad of emotions on Dumbo's face. It's animation, and emotion, at its best.
As a seven year old, watching a re-release of Dumbo at the drive in theater in Minnesota, I remember fighting back tears. As forty three year old man, it still happens.
A heroine is someone who is brave in the face of adversity, ultimately giving her herself in dire times. Mrs. Jumbo takes the honor.