By characters do you mean portraits? The SfP portrait packs work. The portrait packs are not stored in the game folder, they are stored in the same folder as save files. You can find portrait packs to download on the SfP itch page. If you mean the actual characters from your SfP game, you can't import them, the games are too different. It is possible to recreate characters during character creation, but the won't be exactly the same. Cali from SfP is now in Conquest, but she is not quite the same character and has a different image as the character art has changed.