Is theorycrafting here actually means "throws out all imagination and idea on the Apex keyword"? Because I am good at his. Not saying that I could come up with balanced, well designed and characteristic idea, instead I can think of A LOT OF idea.
I am not a native English user, but the word Apex (along with the artworks) makes me feel like that Lord Cooper and his crew are Hunter. And before they can start the hunt, they must first have target(s). Considering the current mechanism of the game (other than adding new Token type), the best way I can think of to represent "picking a target to hunt" is the Adversary condition. To distinguish from the Urami crew, Apex in my idea uses Adversary as a resource that can spend for extra benefit. So the common ability would be like:
Hunt of the Apex: When declaring Triggers in an opposed duel, this model may end the Adversary(Apex) Condition on the opposed model to receive any suit to the final duel total.
Also they are hunting for purpose, no matter it is for food, cash or fame:
Reward Hunting: After this model killed an enemy model with Adversary(Apex), it may draw a card.
And they will need a common Trigger to give Adversary to enemy as a crew that rely on that condition:
Mark Target: Models damaged by this Action gains Adversary(Apex).
I do not have much knowledge of the Lord Cooper since I did not read the background story. But to me, Lord Cooper is more a back line commander who pick the target for his follower and order them to do the job. The main abilities of him are:
Search for Prey: During the Start Phase, this model may discard up to 3 cards and/or Pass Tokens. For each discarded card or Pass Token, this model may target an enemy model within LoS. Target models gains Adversary(Apex).
Stalk to Death: After an enemy model with Adversary(Apex) end its Activation within LoS of this model, this model may discard a card to have another friendly Apex model within LoS of that enemy model to move its Mv toward the enemy model. If the friendly model ends its movement within 8" of the enemy model, the friendly model may take an Attack Action targeting the enemy model.
Other than these Cooper may have some range enhancing ability, like ignoring friendly fire/concealment. In the Attack aspect, Cooper should share similar Actions with Von Schill since they have similar equipment. Only Cooper will have Triggers of all 4 suits in his rifle to make use of the Hunt of the Apex ability. His Tactical Action is about setting up for combat:
Rg 10" | Stat 5 | TN 12
Enemy only. Push any friendly Apex models within 10" of the target up to 3" toward the target. Model pushed this way cannot end its movement within 6" of the target. If the target has the Adversary(Apex), then all models pushed by this Action gains Focus+1.
"Left no exit": Target gains Staggered. If the target has Adversary(Apex), it gains Injured+1.
Ullr & Artemis (Bloodhounds, the totems):
They are weak totem that can only do limited work for the crew. Their stat should be similar or little worse than other hound model. And they have an unique ability to help other Apex model:
Follow Up Attack: When the Adversary(Apex) Condition would end on an enemy model within 2", the enemy model suffer 1 damage.
I am still not yet sure is the word "Model 9" is the name of the henchman, or means there is 9 models inside the box(highly unlikely though). So I now have no idea of what the roles the henchman will fill and what he/she can do for the crew.
They are minion(2), so should be high cost model and the main combat pieces of the keyword. I agree that They may have Disguised or Stealth according to the name and description. Both would be too overkill if we want them to have fighting power at the same time. I would like to see the Beta version of Adversary come back via an ability on them:
Knowing the Prey: This model receives to opposed duels with enemy models that have Adversary(Apex).
According to the artwork, their weapons are shotgun plus knife (and a spear?). Both of them are common weapons spread around all Factions, so there is no doubt that they are using the same profiles with other models. They should, just like the Lord Cooper, have 2~3 Triggers of different suits under each weapons to make use of the ability.
According to the artwork, their only weapon is gun so they should be the mid-cost range unit of the crew. The biggest fear of all range units is being engaged by enemy and cannot escape. The Huntsmen, however, are different. They know how to keep distance with their prey just as good as knowing how to hunt down them:
Hunter's Path: During this model's Activation, it is not treated as engaged by enemy models that have Adversary(Apex).
The minions come with the crew box of Cooper. Look at the artwork and the name I do not think they are combat pieces. Instead they probably a cheap schemer of the crew. From their name I had came up with an Action helping them to move and scheme, but require careful positioning.
Run Away from Threat:
Rg 6" | Stat 5 | TN 10
Enemy only. Push this model 5" away the target. If he target has Adversary(Apex), this model may end the Adversary(Apex) on target to take an Interact Action.
The dual keywords model that shared by Apex and Fae keyword. I believe it is a enforcer beater that around 10ss,. Who would makes a rex a schemer or supporter? Not sure how many abilities it will keep from the TtB, but I believe the Unimpeded, Ruthless and Terrifying will stay. The Rush and Hard to Wound also have high chance to remain since they fit the characteristic. And then I am not sure if it is suitable to give the common Abilities of the Apex keyword since it already has 5 abilities in the front now.
There is no suitable Attack Action for the Rex currently, so it will receive a brand new one (and Triggers for all suits, again):
Rg 0" | Stat 6 | Rst Df
Target suffers 3/4/6 damage.
To distinguish from the Killjoy, the Rex needs a unique Tactical Action:
Rg 6" | Stat 5 | TN 14
Enemy models within range must each pass a TN 10 Wp duel or gain Adversary(Apex) or Adversary(Fae). If the enemy model has smaller Sz than this model, reduce its duel total of the Wp duel by the difference between the Sz.
The Law of the Wildlands:
This model may end Adversary(Apex) or Adversary(Fae) on any enemy models within range. For each enemy model ended Condition this way, this model may take a Action targeting the enemy model.