If they both are rivals with calamity that’s really good! If you can get them to bitter enemies then even if the other two aren’t rivals or better then you still will be in an excellent position in the final battle. Antipathy is an Endgame-level upgrade so you won't see it until after you unlock some of the punisher commanders. The main thing to do is keep it in mind as you unlock upgrades to prevent yourself from upgrading things you may not even use. If you check in the "info" option you should able to find it towards the end in the upgrades section if you really want to map out your upgrade path.
Who to focus on next, honestly your first choice of Calamity I would go for also against this team, her weakness to morality and innocence can lead to some really really big surround turns on her if you play your cards right. And those long turns can lead to a decent chance of breaking the t1 of her confidence. I would be careful though, since Miracle's t1 and t2 confidence are already broken, the relationship between the two would reconcile and maybe even become a friendship for Calamity's 2 confidence relationship events with her. So in that case, if you focus on breaking Calamity's confidence it might be good to break her t1 at first and then try to break Miracle's t2 morality soon after to revert them back to a unfriendly relationship.
Once you've broken the T1 vulnerabilities on chosen, suppressors lose their viability until you unlock versatility or even synthesis down the road. Now would be a good Idea to either use the defiler commanders or a generic commander bodies. Generic Commander bodies are good once you get a grasp of the mechanics to make your surround actions more meaningful throughout the battle. You will still suffer from the reduced damage from their new actions like violence or service, but as their angst builds up the reductions won't help them as much and you can get them to level 1 circumstance damage in one turn like before. And when you get things like extra capture charges and increased durations for your generic commander bodies, your strategy options will increase significantly. Topple that off with networked consciousness where you can immediately pick and action as soon as your surround a chosen and you can get those chosen to t2 breaks/defiler actions pretty easily.
One tip specific to your playthrough though is take note of Spice's Dignity as a minor vulnerability. If you can get her to level 1 EXPO in one turn then it might be good to start the battle against her even if your target may be one of the other two chosen. The multiplier applied to them will really help you stack the damage you need to break their t2.
A strategy I came up from the top of my head is to make a 3-4 turn generic commander or longer if you can already with at least one more capture charge after the initial capture. Then, start the battle with ambushing Spice. From there, do a test run to see how quickly her EXPO raises before reloading the day and trying pummel->grind->humiliate->caress or
pummel->humiliate->grind-> caress. Whichever gives the better results for you. And then using your extra capture charge on the chosen you are actually targeting.
Defilers vary in usefulness but can be very helpful for chosen with more tricky personality traits. Against this team the main ones I can see being useful to you are Ambition and later Vanity for Miracle, or Dominance for Spice, or even Vanity for Spice if you already have a t2 Dignity break on Miracle or you're not focusing on a relationship between the two
Either I hope some of this helps!
