Very simple, at its core that's beautiful to see
Inspiring Word:
I think a 3rd lvl AoE short rest temporary hit point buff, for at that lvl equal to between 4-14 hp, is far too strong. That's also 21-30 hp at lvl 20, for a group, every short rest.
Considering even spells that grant that only grant low amounts to an individual caster (using spell slots instead of offensive magic, etc), and the Battlemaster maneuvers have something similar to this, but requiring far more effort with a much more limited resource.
Plus, coupled to a Second Wind use, that's effectively doubled the 'healing' for a fighter from it to himself, unless he doesn't benefit from it himself? (unclear on that, unless I missed something there?)
Also, needs a duration.
I like that aspect, but perhaps change it running off the Charisma modifier, since that's what the inspiring part is about.
Possibly, even just -half- this amount.
Wolf Pack Tactics:
This is -way- under powered, insanely underpowered. A lvl 7 ability needs way more than giving a bonus action to take the help action.
The Totem Barb's Wolf choice leaves this in the dust, especially since that's a lvl 3 ability.
I suggest using that choice over this, it's the same ability that the MM wolf gets, so it keeps in theme. Though perhaps something different could suit as well?
Lead The Charge:
I like it. My worry is that, does this need the lvl 18 buff? Since at lvl 17 the fighter gets a second action surge, that already buffs this up to double power. Twice per short rest AoE extra attacks/moves for possibly the entire party is pretty damn huge, even once is horrendous. At least early it's just a single ally, which I feel is really nicely done and balanced
This could even be moved to the lvl 7 slot, too, power level wise.
Hold The Line:
Fighters should not have the ability to heal overs, and the effects of this ability compared to the theory behind 'holding a line' is a bit different. Hold the line implies the morale rationale, maintaining the right frame of mind and what not. I think that if you want something 'hold the line-y' you'd be better having something reflect the ensuring the line holds, maybe giving allies a higher AC or reaction abilities or something to do with an anti-fear / terror / charm aura style.
Also, without a limit to the uses you can just have characters expend hit die and heal repeatedly at a fraction of the rate a short rest can, which is one of the biggest reasons a short rest happens.
Definitely needs a limit, perhaps something like 'each target can only benefit from this once until successfully completing a short rest' kinda disclaimer, to stop the spam.
Overall, I still see that this archetype should benefit from a proper capstone. Lead the Charge shouldn't occupy that slot, imho.
Nice overall, I does likes.