This one is pretty hard. Whichever way it goes, it will likely be close. For now, I'm leaning towards Claire.
With Claire's starting range advantage, she's free to cast a barrage of Fireballs and Fire Bursts, boosted by Flames of Elstein, something she has done. With both of these spells' large AoE, some of the zombies, if not all, can be dealt with (or at least deal significant damage). Boar's guns aren't much of an issue with her Instinctive Reactions. When they get closer, End of Vermillion and Frost Blaze, her strongest spells, should do it. Claire is also consistently effective at fighting multiple opponents at once.
With such an initial disadvantage in numbers + starting distance, I don't see Claire using her whip, instead using her spirit. She's plenty strong as a cat, but her human form is much more powerful, surpassing Claire, and defeating opponents Claire was struggling against.
If Rabbit or Monkey get close, it will be much harder for Claire, but as long as Ortlinde is around, I believe it's winnable for her even then.
