For now, no, you can't get both of them to 400 power. Maybe in the next update, we will get their cap raised to 400.
But for now, again, no. Leah is the only char for now that can reach 400 power.
Alr ty for the info. I was just walking around for a bit in-game and found out that to get Valorie to 400 power along with Leah you need to complete the Witch Academy event which will allow you get the power cap on Leah and Valorie. *SPOILER ALERT IF YOU DIDNT FINISH CHAPTER 3* You will be given a flying ship which is fast and a easy way to travel.