I haven't used any, but imagine it would depend where your stats are now. Unless he specifically wanted to test edge cases, I doubt the dev would have accounted for situations that aren't actually possible without cheating, such as positive relationship with Keirys and Snake after they've already been locked out. (Though, at least in my save, Snake's actually can't be changed, but Keirys's can for some reason). So those could result in some weird situations.