I've replaced Lysithea with Cornelia in this save file, and also replaced the following:
Linhardt -> Hanneman
Raphael -> Alois
Caspar -> Thales
Petra -> Kronya
Ashe -> Solon
Ferdinand -> Nader
Lorenz -> Rufus
As for how you do it, it's a bit complicated, I just used Kimkadamura's findings as a...