A couple of things that I would change would be the warrior's martial skill to one with Impaler. Since you aren't playing chops and are playing penetrating attacks, the damage bonus will help a little. I would pick a weapon for your priest without Demonic Revenge on it. I like to use either St. Trobor's Maul or Blessed Club for healing, or True Strike Spear, St. Portia's Maul, Vigun's Blessed Blade, Vampire's Blade, or Club Of Wrath for damage. If you're using Firestorm, a good setup for the priest is Shoddy Healing Tokens for divine items or Small Healing Orbs with Rusty Healing Armor, Holy Chainmail, Dark Chain Shirt, or even Mail Of The Novice if you can stand the encumber. I like to use Novice Piety Divine skill for the card draw and 2 traits then focus on stacking heals in all the other slots when I use Firestorm. An easy to obtain armor is Thick Healer's Hide, which gives you a couple more healing spells to trigger Altruism with. You may consider using Glimmer Boots if you decide to go the healing route on the priest since it gives you a trait which doesn't matter for a healer along with Hardy Mail. Goat Boots are another decent option for the armor and trait. Your wizard setup looks fine except maybe for the dwarf skill. I would pick Stout Charger since when using FS you need all the armor you can draw as soon as possible and having the Charge can help a lot on the 3rd map of Defense of Woodhome to get to the victory point on the first turn. On that map, I just keep moving back from the uber skellies unless to do so would mean abandoning the victory squares. Just try to tank with the most armored character and keep healing him. I hope this helps, and feel free to ask about something that I didn't cover if you still have questions.
I try to buff crushing damage for Woodhome to deal with the skellies in 2 & 3. If you run 1-6 much you should find some Hefty Stout Clubs which will give your fighter a boost. If you don't have good crushing weapons for your cleric, consider vampiric. Armor stripper helps a lot in Woodhome 3 as well. That's the point where I normally swap some gear.
Do you hate War Monkeys as much as I do? Do you want to have an even more unfair advantage than they do? If so, then this build may be for you. It has been very consistent for clearing all the level 16 adventures without losses, using 2 priests for tons of buffs and good consistent damage from the warrior. I tested this build for the level 15 gnome adventures along with the level 17 tree adventure (Black Oaken Heart, I think) and it works incredibly well. For the 15s, I sub Raging Rock in on the dwarf priest, Infused Greatclub in place of The Hackmaster on the warrior, and Azure Boots on the human priest. For the level 17, you can add whatever you think you need. SRC_Brina Bronze-Hammer Level 19 Dwarf Priest St. Olf's Fiery PikeNimbus BladeBurnished PlatesRusty BucklerGoat BootsShuddering RelicShielding TokenShuddering RelicSolid RockAdvanced Piety1 x Frenzy Aura3 x Parry1 x Greater Heal1 x Unholy Frenzy1 x Strong Bash1 x Dodge1 x Martyr Blessing2 x Stab2 x Immovable1 x Weakened Armor1 x Dangerous Maneuver4 x Mass Frenzy4 x Impenetrable Nimbus1 x Polearm Slash2 x Altruism3 x Fiery Stab2 x Enervating Touch1 x Toughness1 x Team Heal2 x Vulnerable1 x Consuming Touch SRC_Auriel Level 19 Human Priest Duality MaceSt. Portia's MaulBurnished PlatesSlippery ShieldGreenguard BootsTome Of The MartyrShuddering RelicIncense Of Roiled AirSuperb CommandAdvanced Piety1 x Frenzy Aura1 x Parry3 x Inspiration3 x Consuming Touch1 x All Out Attack3 x Martyr Blessing1 x Vulnerable3 x Strong Bludgeon1 x Teleport Self2 x Mass Frenzy2 x Impenetrable Nimbus4 x Hard To Pin Down1 x Shuffle, Team!1 x Squeamish1 x Enervating Touch2 x Touch Of Death1 x Team Heal1 x Greater Heal1 x Lifesaving Block1 x Chop2 x Altruism SRC_Gwyne Level 20 Human Warrior The HackmasterBejeweled ShortswordThe StrongarmPerilous RingmailSlippery ShieldAngry Jack's HelmetGoat BootsSuperb CommandSuperb Impaling1 x All Out Attack1 x Weak Strike2 x Impaler1 x Weakened Armor1 x Impaling Stab1 x Dangerous Maneuver1 x Blind Rage2 x Vicious Thrust10 x Strong Hack1 x Thickened Mail1 x Traveling Curse1 x Walk, Team!1 x Almighty Hack1 x Immovable2 x Reliable Mail1 x Powerful Bludgeon3 x Powerful Hack3 x Hard To Pin Down1 x Parry1 x Shuffle, Team!
For the level 12 adventures (it works for the level 13 with no change also) i use a 1 wizard firestorm, 2 warrior team. If you don't draw any armors for the warriors on the harder missions maybe wait 1 turn to fs. For the last mission in temple of scales i swap in my 1 lochaber axe on a warrior to help deal with the slime that starts behind you. Karazok Level 20 Dwarf Wizard Wym's Lavastaff Wym's Lavastaff Brin's Storm Locket Morbo's Pendant Penteth's Orb Yaro's Scepter Firehide Robes Vira's Shoes Untrained Stoutness Focused Pyromancy 2 x Immovable 4 x Volcano 3 x Firestarter 1 x Penetrating Zap 1 x Walk 1 x Cone Of Cold 1 x Forgetfulness 2 x Shimmering Aura 1 x Teleport Self 1 x Short Perplexing Ray 1 x Reflexive Teleport 1 x Path Of Knives 1 x Resistant Hide 15 x Firestorm 1 x Trip Zhufdar Level 17 Dwarf Warrior Infused Greatclub Infused Greatclub Nifty Halberd Xander's Mail Parrying Buckler Angry Jack's Helmet Kerrick's Steel Boots Apprentice Ferocity Superb Impaling 3 x Parry 2 x Nimble Strike 1 x Impaling Stab 1 x Shuffle 2 x Officer's Harness 1 x Able Bludgeon 4 x Obliterating Bludgeon 1 x Walk, Team! 3 x Weak Chop 2 x Trained Bludgeon 4 x Reliable Mail 6 x Bludgeon 2 x Impaler 1 x Desperate Block 3 x Blind Rage Thagzhuf Level 17 Dwarf Warrior Infused Greatclub Infused Greatclub Nifty Halberd Wex's Mail Parrying Buckler Angry Jack's Helmet Kerrick's Steel Boots Apprentice Ferocity Superb Impaling 3 x Parry 2 x Nimble Strike 1 x Crafted Mail 1 x Impaling Stab 1 x Shuffle 1 x Able Bludgeon 4 x Obliterating Bludgeon 1 x Walk, Team! 3 x Weak Chop 2 x Trained Bludgeon 3 x Reliable Mail 6 x Bludgeon 2 x Impaler 2 x Shimmering Aura 1 x Desperate Block 3 x Blind Rage