FW: Route-Exclusive Advanced Classes?

One more mechanical spoiler post from me. Want more posts on this, or at least a French speaker to translate.

Looking around for a screenshot on where automaton Orchel comes from, I randomly stumbled upon this French preview. This section intriuged me the most.

Après un entraînement adéquat (arène, escarmouches, gestion auto...), vos unités peuvent passer des examens pour changer de classe, modifiant leurs statistiques, leurs armes de prédilection et leurs capacités. Si le catalogue de base semble sage, chaque trame réserve ses propres classes supérieures exclusives (un Mage Noir monté sur Ornius chez Cai, un Lancier Mage Blanc chez Dietrich et Theodora...). L'éventail de progression est bel et bien là, même s'il manque encore cette petite étincelle d'émerveillement pour totalement me convaincre.

Running it through translation software gives me:

After proper training (arena, skirmishes, auto‑management…), your units can take exams to change class, altering their stats, preferred weapons, and abilities. If the basic catalog seems modest, each storyline offers its own exclusive advanced classes (a mounted Dark Mage on an Ornius for Cai, a White‑Mage Lancer for Dietrich and Theodora…). The range of progression is definitely there, even if it still lacks that little spark of wonder needed to fully win me over.

We definitely know there are hidden classes spread throughout the game, such as Leda's Dancer or Dietrich's Swordmaster. But now I'm wondering what classes each route could be hiding, and if they also apply to Master classes? I'm also prone to taking this info with a grain of salt, at least? This article seems to be breaking quite a bit of the embargo, but it does seem that the French people got a little more leeway in general.

Again, would like a French speaker to help translate this.