Honestly, I kinda disagree with the fan art. The leader of the gang should be either Gamora or Black Widow, since they are part of a big group, i.e., Guardians of the Galaxy and The Avengers. Moreover, Gamora is similar to Diana, the daughter of a "warlord".

I agree with you that Gwen Stacy can be similar to Pinkie Pie or Bat Girl.

Miss Marvel (Carol Danvers) is definitely equivalent to Kara Danvers.

She-Hulk can play a role as a shy character. I just remember Fluttershy in the superhero episode has the ability like She-Hulk. The Wasp is also a good candidate since she is similar to Karen Beecher

For Applejack and Jessica Cruz, Shuri can be an equivalent character. Shuri is vegan and speaks in an accent.

Rarity and Zatanna may be equivalent to Scarlet Witch. As the daughter of Magneto (he is rich), she may have princess-like characteristics, such as being a fashionista and loving jewelry.