Divine intervention is tricky and only as powerful as the DM decides it is. This is typically just a free spell and the the corresponding saving throw (and resistance) still applies. I'm not familiar with the winter queen though.
Also, reading through your list of monsters I'm not surprised if it was an easy fight. When monster's CR are significantly below the average level of the party they don't count as much as you'd think. That and I never take into account the numbers multiplier, I just add up XP on both sides.
So at best by my calculation guesstimate you may have thrown 2 medium encounters. Given those were the only two fights of they day I'd be surprised if they even broke a sweat.
Also, reading through your list of monsters I'm not surprised if it was an easy fight. When monster's CR are significantly below the average level of the party they don't count as much as you'd think. That and I never take into account the numbers multiplier, I just add up XP on both sides.
So at best by my calculation guesstimate you may have thrown 2 medium encounters. Given those were the only two fights of they day I'd be surprised if they even broke a sweat.