dont know if someone said these but...
the generic generals in part 4 can use all 3 weapons
Male Halberdiers have a lower minimal cap for Weapon Rank then Females
Rexbolt is the only attack in FE history to be able to attack someone up-front but doesnt focus on the Characters all the time(Bolting in the GBA games does this but cant attack up-front)
Micaiah is the only FE lord to not be full human/beorc(FE4 doesnt count since Siglud/whatshisname were still full human)
Edward is the only Myrmidon in the only Myrmidon to have 60% Str without items that boost Growth Rates
Ike is the 1st FE lord to show his muscles without Fan-art(Hector had armor so you couldnt see his muscles i think)
This game has the least archetypes
This game doesnt give the 1st lord a unique legendary weapon (FE1-3 had the Falchion,FE4 had the Tyrfing, FE5 the Blagi Sword, FE6 the Sword of Seals and it goes on)
And this game is the 1st American game to have leadership stars(after the insanity that was FE5 and whatshisnames 10 leadership stars UGGGGGH)