It’s so peak…
By my count to make FE6 complete, you would need:
M+F Hero (Durandal and Armads) (Linus M Hero could work but isn’t strict to FE6)
M+F Nomad Trooper (Durandal)
Falcoknight (Durandal)
Wyvern Lord (Durandal)
If you choose to do a special bow design too: Sniper, Nomad Trooper and Warrior.