DDD 3H Class Decision Assistance List (Non-Maddening, Non-NG+ Difficulty)
Pally has Cavalier (D+/D skills) to dual train Lance/Riding with the class-bonus skill ranks on-map. Wyvern Lord needs Wyvern Rider(C+/C) to start training with on-map skill bonuses. Massive preempt time sink difference for Catherine(late join E's with additional missing chapters). Flier stride=DLC.
Credit to https://fireemblem.fandom.com/wiki/List_of_characters_in_Fire_Emblem:_Three_Houses for the images.