a.cs

public class CommandWindowManager: MonoBehaviour {
  public class CreateWindow(Array<(string, Action)>) {
    // コマンドボタンの作成
  }
}

public class BattleMain: MonoBehabiour {
  void CreateCommandWindow() {
    commandWindowManager.CreateWindow(new Array<(string, Action)> {
      (
        "攻撃",
        () => {
          // 攻撃対象選択待機に移る処理
        }
      ),
      (
        "待機",
        () => {
          selectedCharacter.Wait();
        }
      )
    });
  }
}