Those are some creative ideas for the handling of these case. I think by design originally, this was the only battle that actually had this event span across days, at least as far as I remember, but it would be interesting to add it as a mechanic for every enemy.
I'm more reserved with the first option of intentionally allowing the player to choose the game over, when you already have a path that forces it, however the other 2 options would be very rewarding to implement. Either allowing the battle to restart the next day or having the option to escape. This would reward the player with a day reset, giving back the 10 actions per day, but resulting in a more depraved penalization as you said.
I see, the problems with the scenes cause silent, but "recoverable", crashes in the engine (recoverable on the engine side, but not on the scene's code), hence why other systems like the sound and even video, may have problems as a consequence of errors in code for totally unrelated things.
The rollback in the "Preload Anims" setting is possible, but not needed with the next version. The problems are already fixed and somewhat tested. "Long Animations" can't be rolled back because the option was there since the first version
. That is to say, the setting can be removed, but its implementation is too simple to not just be fixed in the future, instead of just removing it, unless no one is interested in the extended versions of the animations. This option is also from the original game, but I defaulted it to OFF instead of ON, like in the source.