farm loosing to get the gold, avoiding the character who can stole your gold and after you easy run victory on everyone (but they have an order of difficulty kat and the queen are the 2 i focus the win in last i go win on the others first) i think there are some playthrough with the order you can win them and which stuff you need.
and as sample lux first fight is free to win she let you do enought attack move before begin really the fight so it's hard to be locked in story
the only thing you need save before is to unlock sortilege than lux can learn you becose you need to perfectly answer all. (so you just need save before any time you go see lux in case it's the sortilege training.
Sometimes you just get unlucky in a fight, just lose and the next day it's more easy (i have never use any heal during fight first win and second win and never change any gamedata to boost attack etc)