You should have a look at the fe7 reskins and think about what you want to do to differentiate your project from those ones for a unique or more enjoyable experience
Also, it’d be pretty simple to give all enemy classes between +20% and +30% growths in each stat, which I think has been done before to just raise the difficulty curve.
I have no idea which reskin I would choose if I wanted to replay fe7.
Anyhow, I hope it’s a rewarding experience and good luck with the project.