War Cleric is actually an interesting alternative to Fighter and Barbarian. Divine Favor gives +2,5 damage per hit and if they can maintain it for one turn, they can get a bonus attack about twice with a reasonable chance of success. I think it ultimately leads to a faster victory though of course, there are way more variables with the Concentration suddenly becoming a thing. But if we have a +6 to attack 1d8+4 weapon and cast Divine Favor and successfully get two attacks off and have Bless active, that's 7,775 per attack for 15,55 average damage. It's a bit over 7 attacks to drop the Enemy this way but the key difference is that the bonus action attack means that can be done in 4-5 turns. I think we're on to something here; this way it's really quite likely for our hero to win. Of course, alternatively it's possible to also just hit with Inflict Wounds or Guiding Bolt but of course, that costs you a spell. With two per day, Divine Favor x2 or Divine Favor and Healing Word seem like the way to go (you never wanna skip your attack since you need to finish this ASAP) and since your stats will be 16 Dex / 16 Con, your spell attack will be mediocre anyways (+4 vs. +6 on your weapon attacks). Though I guess going 16/14/16 is reasonable if we're just planning on not being hit very much.

As for Barb, it's good but Rage isn't that useful since the primary issue is the breath weapon; though neither of course does much there. With Ceremony we can reach AC high enough to mostly not be bothered by Enemy's melee. Potentially still the best option just due to having d12 HD for those couple of extra HP.