Dietrich route development: Warrior for Strength, Ranger for Speed and DexterityMinor spoilers
Choose growth classes around actual weaknesses. Myrmidon and Shido can be mastery stops; improve armored mobility, use Io's built-in mount, and give mages additional utility.
Original video: Fire Emblem: Fortune's Weave — Recommended development classes for Dietrich's route | Bilibili creator Dr__W
Use Gladiator and Brigand early to improve Dietrich’s Strength, then choose Warrior or Ranger at Advanced according to weaknesses. Myrmidon and Shido can be mastery stops, with leveling done in classes providing more-needed growth.
Change Dietrich's class to address growth shortfalls
Dietrich has a strong physical damage foundation. Start with 
Gladiator and 
Brigand for Strength, then inspect actual gains at the Advanced tier. Choose 
Warrior if Strength is low, or 
Ranger if Speed and Dexterity are lacking.
Master 
Myrmidon and 
Shido without necessarily staying in them for long-term leveling. Mastery and growth can be planned separately. Add 
Sacred Gem for sustain once the build is ready.
Add movement to armor and use Io’s mount
Esmeralda and 
Goliath have high Strength and Defense with suitable front-line abilities, but move slowly without 
Armored Move. 
Gaitz becomes usable only in Chapter 12, yet still has Strength and Defense for the front.
If four Movement feels too restrictive, consider 
Guardian, also adding some Resistance.
Io comes with a special mount and cavalry-linked abilities, making mounted development worthwhile even outside 
Cai's route. Switch sideways to 
Charioteer to keep using the mount, and consider staying there past level 35. Bring 
Mini Bow for close-range counters to cover a front-line bow user's range weakness.
Build Strength for gauntlets and pair status effects with Tyranny
Mikaela has ordinary total growth, but her personal ability directly adds Hit and suits gauntlets. Her Combat Arts include anti-armor options, and she can learn a purifying fist art from the protagonist. Continue into Ranger or stay with gauntlets. She learns Armored Move and has decent Defense growth, making an armored frontline role another option.
Ursula, 
Jester, and 
Kiroc have good Speed and Dexterity, so prioritize Strength. Ursula joins through a paralogue. If development is awkward, she can support as 
Dancer instead.
Kiroc needs an enemy status effect to benefit from 
Tyranny. Equip teammates with 
Venin Edge and Venin Bow to apply it before he attacks.
Regular mages and a melee Priest
Fabio, 
Yang Jie, 
Dante, and 
Sha Lan can follow conventional mage paths.
Yang Jie also has a distinctive option. Start with 
Mace and Combat Arts for magical damage, then use magical arts such as Lightning Axe later. This applies Magic to melee attacks instead of limiting him to rear-line casting.