Aha! I am making a perfect armor emblem team for use in arena and stuff and I want to see what people think the perfect combination is.

I don't think Warding Breath's Special charge time effect stacks with Vengeful Fighter.

Effie, Grima, BK and Bonus unit/Amelia/Winter robin.

Mine hauls ass on defense; Henry carried me to so many defense victories

Effie for sure.
Grima for sure (ideally, he wants Distant Defense 3 in the A slot).
Either Black Knight or W! Tharja (I'd go with BK, since you already have Grima as a source of magical damage, and he'll score higher).

As for your resident Armor March, either W! Robin and Amelia are fine (I'd go with Amelia, but because I like running double green armor), but you should try to get DC and Bold Fighter for whichever you pick.

Also, ditch the Fortifies and Ward up.

Personally, I run Effie, Sheena and Zelgius as my core, and either Grima or LA! Hector (I have enough 5* armors for literally 3 teams).
Sheena is amazing, and can be easily merged up with feathers.
If you get a good one (+atk/-spd or +res/-spd), give her a chance and you won't regret it!