Armor Team builds

Current Team: +def -hp Winter Tharja, +atk -def Hardin, +atk -res Fell Reincarnation Robin.
Potential units: +def -res Amelia, +atk -hp Effie, +def -hp Normal Hector, +atk -res Winter Robin, +1 Black Knight, +1 Arden.

I just got a +def -hp winter Tharja that I want to use with my armor team currently consisting of +atk -def Hardin(replaceable with other blues if there is a better option), +atk -res Fell Reincarnation Robin(replaceable with other greens if there is a better option, but I want to keep magic damage if possible), and finally I am unsure of who to use. My Robin has warding breath to negate his -res as well as aether to go along with his base kit. My Hardin is using QR3 seal to make him multi phase as well as his base kit. I also have a bunch of other armors that I could use, unfortunately I have no idea who to use. I have a +1 Black Knight who is using his default kit, a +1 Arden who has deathblow 3, follow up ring, brash assault 3 sacred seal on him, a +atk -hp Effie using brave lance+ and deathblow 3 and wary fighter 3, a +def -hp normal Hector using distant counter, vantage 3 and goad armor, a +def -res Amelia using fury 3 and renewal 3 with armor march, a -atk +hp Valentine Lyn with her default kit, a +atk -res winter Robin with a +def tanneboom, vantage 3, and armor march. I also have a spare Amelia for fodder as well as a spare winter Robin and a spare normal Hector.

I like Tharja over BK because she is a truly spectacular tank, a far better one than my Hardin due to his -def, and I want to split damage between physical and magic. The final team I want to be half physical half magic if possible, it's just a question of who to add. I also think I may give Tharja armor march from my spare Amelia, as I want her to have it because as the tank she is not likely to die and she becomes a monsterous tank with buffs, reaching up to 45-49 def/res(with a refined candelabra).

I have all of the armor buffs available for fodder for all of my units mentioned so don't worry about that as a limitation. I have these A skills to fodder: deathblow, steady blow, close counter, distant counter, fury, triangle adept, and steady breath. I have these B skills to fodder: sword breaker, lance breaker, axe breaker, vengeful fighter, vantage, desperation, wary fighter, renewal, quick riposte, bow breaker, cancel affinity, all tome breakers.

Sorry for the text block, but I want to finally finish my optimal armor team, and thanks.