I think Valeria Richards is the most underrated Fantastic Four character in the comics, so I would love to see her in the MCU. That said, I can't see it happening in The Fantastic Four: First Steps. After all, Reed Richards and Sue Storm's older child, Franklin Richards, will be born throughout the film. With Galactus, the Silver Surfer, Franklin, the whole team, and more to set up, I think there will not be enough time to drop teases that Valeria will one day come to the MCU. That said, I would love to be wrong.