Just to address some things here:
So how does the actor change class?
Through either a quest or an item they can buy if they exchange enough gold to get Silver (ingame premium currency. Rate is: 10k Gold for 1 silver.). The quest is sorta easy, but if they don't wanna do quests, I give the choice of an item if they have enough silver.
If you are using a plugin to change classes then I don't see why. If the player cannot change back to a previous class then what is the point of using a class change plugin? Why not use use an event to change the actor classes?
I'm doing both events and a plugin. I use the events to do the quest and class change and the plugin for the visual change (Yanfly Class change core.
<Class x Character: filename y> and
<Class x Face: filename y> is what I am using for the first four actors).
Each character has a separate class tree they can go down: Dark and Light (e.g.: Dark Knight or Light Knight). Dark has 2 class advancements (e.g.: Honor (base class), Dark Knight (1st Dark Class), Berserker (2nd Dark Class)) and so does Light (e.g.: Honor (base class), Light Knight (1st Light Class), Gladiator (2nd Light Class))
Each set of classes has their own buffs/nerfs to stats, so Stat Allocation can either make up for the nerfs a class gets or maximize their buffs they already get or go down another path by injecting points into another stat.
I don't allow backtracking yet because I haven't gotten there yet. I want to make sure this part of the game is done before I allow it because the way the Stat Allocation works rn ingame, it would make things hard and confusing.
If you are changing class through an event, then you should be able to store the actors parameters in variables and then use those variables to reset the actor parameters once they have switched classes.
How would I go about that with Stat Allocation? I know I can with regular stats, but is there a way to store invested JP into a variable from Stat Allocation and push it to the new class Stat Allocation?