For the purpose of reactivity the origin characters will still count as having their original class and not the respecced one. So instead of reactivity checking the class a character has they now have a class for cutscenes and a class for gameplay.
Also its not only cutscenes but also quest design. Now you cant have for example a personal quest for Halsin that requires him to use wildshape to get past obstacles because the archdruid might not be a druid anymore.
No, they do not have a class in cutscenes. They have pre-rendered animations and actions. A class is part of a game system. Their class won’t match the pre-rendered animations and narrative of the cutscenes, but that doesn’t take any extra work for Larian, so this doesn’t further the point you are trying to make.
A quest for Halsin that REQUIRES him to use Wild Shape would never happen, as Larian don’t design quests where there is only one way to completion requiring a specific skill to be used.
Sorry, but you are really just grasping at straws.