Hello Ero!
After looking throughout this issue and doing some more tests, I came to the conclusion that due to how RPG Maker games saves the data, the fix on the classes will only work in new files and cannot be override even if the source is corrected, so since you and others are enjoying the game so far, in order to not start from the beginning, I'm preparing a patch to fix the classes.
In the meanwhile if you wish, if you start a new game with the other character you'll see the classes will be as intended from the start.
Thank you very much for trying the gam and making me aware of these issues, working way too much and sleeping for few hours a day is taking a tool on my attention to these details!