Best fighter skills

So I have summoned 4x total on this banner (or 13 orbs considering the free summon then resummoning pool) for the fighter skills. And having said that I had this monstrosity of a pull. I have never gotten anything like this, but goddamn did it feel good, especially getting a second Hardin. What I am curious about is if I should give my +atk -res M!Grima bold fighter, my BK bold fighter, or my +def -HP W!Tharja bold fighter. I have 3 M!Grima now, none of them merged so I could +2 him if I wanted, and my BK is +2, my W!Tharja is +0.

The pulls I got for this summoning are +def -HP M!Grima, +def -res Effie and a +atk -spd Hardin replacing my +atk -def Hardin as the -spd bane is way better outside of it being a super bane.