I think one mistake I often see people make in alt activation games is take a small force of expensive models. There is really power in having MORE activation than the other guy. This is, IMO, where the real power lies in a gremlin force. In my experience, the sheer number of shots nd bodies a gremlin force can have can drag down an elite enemy.
I've played Perdita only once, but even her box has 5 models and some of those are expendable/throwaway activations (unless you just have the whole family go) where others are great 1st activaters, capable of outright killing an enemy unactivated model.
But I know Justice far better, so I'll talk about that.
Justice also has 5 models. If I'm playing a box game, I use the Judge as a speed bump and stagger the marshalls. The Judge is a big threat that alot of people fear, but his range is shorter and he's not as efficient at range as melee, so I like to get him up there and let him soak it up.
The marshalls are FANTASTIC at piling on ranged damage. They can drop similar 4 stone models in two shots pretty easier with crit strikes. And I get 3. After the Judge makes a threat move, the marshalls can begin to respond to enemy positioning, laying down a field of fire that can allow them to threaten an equal number of weaker models or combine to beat up on a harder threat. These guys in numbers are the real power of the Justice set. They are the mid-turn activaters that are going to be cranking out most of the damage while people are ignoring them in fear of Judge/Justice.
Justice is the last piece. She's normally the model I activate last (we'll get to that in a minute). She's also the one most people worry about. But she is really my clean-up crew. Early and mid-game she doesn't do much but threaten. It's her imminent activation that seems to make most of my opponents sweat it out over what to do. She hasn't gone yet and there's the Judge in their grill with 3 marshalls laying down cover fire behind.
Maybe I'm weird, but I very frequently put Justice on a far flank. The Judge and marshalls come up the middle (sometimes the Judge flanks one way or the other too) and Justiec flanks. This really throws people off. She doesn't seem to be in the game, but she can be in any given turn. It's a HUGE threat that activates last each round and as the game grinds on and they get weaker, it gets scarier.
And that's the power of a fast, heavy flanker. Justice is a death machine with a solid defense (plenty of stones to stop damage + riposte for melee). She's a weight hanging over their head every turn, waiting. It forces their activations and tends to let me control the pace. Then, when I've softened them up with a slow advance of marshalls and bullets and stuff in gummed up in the middle and beat up, Justice rolls in and sweeps up the mess. That's when she goes from activating last to first.
And that's the other side of it. I mention 5 models cause it matters. In a 30ss game, I can take a Justice box with 5 models, 4 of which are ultimately disposable. BUT, I will often see people take 4-5 models + a healthy amount of stones. This means I am equal or better in activations, and my ranged abilities are often better than theirs and/or I simply have a further range. This lets me get ahead in activatiosn early. Then I can sac a model to force them into a killbox. I can afford to throwaway a model early if need be to force an activation on their end.
I often see carefully constructed forces where every model is dangerous and plays a key role in a plan...but each is necessary for that plan. Losing one will often throw it off. But when I can afford to lose a model or to throw one out to die in order to get a leg up on numbers of activations, I will win that game.
I think that's why cheap hard hitters, especially cheap ranged hard-hitters are a great tool in alt action games. If you can draw a small elite force into range, you can trade blows in the early turn activations softening up models, then late turn kill them. Once you pull ahead in activatios, you can start beating up unactivated models every turn, further sapping their strength. But throwing that threat model out to draw them into range is key. If you have all threat models and no expendables, it's alot harder to do.
Perdita is so sick because Loco and Santiago ar prefect throwaways while Nino and Perdita are great earlier activaters than can hit with little to fear in return. Fransico is a good damage dealer to pick on models drawn in. And then when you're ready, you family up and have one huge activation of death.