Avengers! Black Widow is an awesome, strong character in both games, and AIQ also adds the crazy powerful Captain Marvel (probably the most powerful of all the heroes honestly) and Wasp, who awards your extra ball.

Stranger Things heavily features Eleven, who is another very powerful female character, and I am guessing closer to your daughter's age bracket, so more relatable.

While I see the disappointment that April isn't a playable character in TMNT, you can point out that she is a VERY powerful ally in the game. She awards big points in her hurry-ups, but more importantly literally saves your turtle with her ball saves!

edit: Gah! Can't believe I forgot about Wanda in AIQ! I wish she had a bigger role, but Scarlet Witch is definitely there, and she's one of the few characters that might give Cap Marvel a run for her money as strongest character!

Also GOTG has some badass women in Gamora and Nebula. Marvel has really embraced empowering women in the MCU. Some may think it's over the top, but I think it's awesome and well done.

I wish we could get a Wonder Woman machine!

X-Men is another with strong female characters! 3 of the 8 heroes are women, Storm, Rogue, and Phoenix. And really, they could kick the male heroes butts pretty easily! Lots of cameos from other female X-Men throughout the game too.

Deadpool features two female team-up allys, plus Dazzler being featured in a multiball.

In Star Wars you can choose Princess Leia as your character, with her own scoring advantages.