Module

Are you talking about the module when you say 'liberation'?

All of them are quite the lineup! I don't have these characters on my Rhodes Island, so I'm not sure about the difficulty or capabilities of their modules, but are they perhaps Executor or Młynar? Though Młynar seems difficult to handle, and I don't know where Executor's module unlock is... I'm currently raising Ines and Saria, so I want to unlock their modules, but I haven't unlocked the main story or episodes yet, so neither has their module unlocked lol. If your main story is progressing, Ines seems like she'd be easier to unlock modules for~

Vanguard 2, Guard 7, Defender 3, huh? Having 0 high-ground operators likely means prioritizing the strengthening of ground units. Penance and Hoshiguma, while Defenders, are attack-oriented and both have high survivability, so they might be lower priority. For Surtr, even though her healing increases, it's better to consider synergy and integration with Medics. With 7 Guards, it's inferred that strengthening this class is a priority. Considering offensive impact, Degen & Mlynar would be the first choice, with Blaze as a secondary option. The former two have overwhelming attack power and survivability, so they won't be a waste even at Stage 3. Blaze's primary skill is likely S2, and her modules focus on survivability, making her durable and capable of AoE attacks, which is strong. Other Guards include Dusk. She requires constant micro-management and is technical, but with module upgrades, her SP regeneration improves, making her easier to handle. If you find her useful, Ch'en's Stage 2 significantly boosts her skill cycle. For Vanguards, if you want either a cost buff or an attack speed buff, consider Saileach. If your focus aligns with redeploy time reduction and high damage, consider Ines.

For me, it's Ines, Blaze, Surtr, Altered Hoshiguma, and Muelsyse. Isn't it tough to get them to level 90?