I broke down and bought the Pagoda myself. I've ran it a couple of times now, and the mechanics are not that bad, but I'll tell ya, I'm not yet able to solo it myself. The most common schools you will face are Fire and Balance. There aren't that many fights, and if you google Midnight Sun Pagoda guide, you'll get a basic rundown on which fights are what.
I want to go over how I deal with the three cheat boss fights. And also mention that the grave marker puzzle is really easy. You can visually tell which grave is oldest to newest by just looking at them, the most ragged and worn is the oldest, so just keep looking for the worst damaged marker and clicking it, until you're left with the perfectly whole one. There's no time limit that I can tell, so no need to rush.
OK. The three cheat bosses.
The first cheat boss you meet is Kurogawa. His cheat is that if you damage him when you have no shield on you, he will get a free interrupt cast of vampire on you. And every other round or so, he will destroy a shield on someone. One guide mentioned that you can attack him without a shield on you, just not on the turn he removed it. Whatever. You got two options as the pyromancer. Do a lot of damage and not care that he is getting a free hit on you. Or do a lot more damage as a one-hit kill. If you're lower level, it might be better to coordinate with your group and kill single targets one at a time, saving Kurogawa for last. Then have one guy build up for a big hit, while everyone just shields as best they can, taking whatever damage opportunities they have while shielded.
EDIT: If you attack his minions without a shield, he still gets a free vampire. Oh boy! If you do AoE spells while shielded, this is the quickest way through.
The next boss is far more complicated, and can get seriously messy for the group. Yoshinobu is storm school. However, he and his crew have interrupt casts from all sorts of schools that don't match their own. Their interrupts are based on a very specific trigger - damaging Yoshinobu. As I've found out from other cheat bosses, there seem to be some exclusions to this rule that are a bit hard to figure out, but just generally, don't attack Yoshinobu until he is the last cow standing (he's a samoorai). OR! You can always do my favorite trick: one hit killing him. What makes that difficult is that they like to do a lot of shielding - legion shields and school shields. One suggestion was to do an earthquake on the group to remove the shields, but that of course will trigger his cheat mechanic. So what is the cheat mechanic? It is called "Chain Reaction", and it's effects vary upon the level of the encounter. I went in with a low level group, and his chain reaction was to cast a -60% smokescreen on everyone, followed by unicorn spell for his group. The higher level encounter was more ouch - same smokescreen, with a rebirth for his group, and a Power Nova.
To make matters worse, the entire fight starts with a free cast of mass infection by the enemies, and every couple of rounds a free cast of legion shields.
The final fight is with a guy named Kaizoku, a war pig. The fight starts with him putting up a very large tower shield (around 75% damage reduction, possibly higher for the higher level fights). Every other round (according to one Wizard 101 wiki entry), he removes all shields on your group and himself, and does a 150 point Star Attack. If you put a trap or negative charm on any enemy, Kaizoku interrupts and removes it for free. Every time he takes damage, he interrupts after the damage to put up another shield. Like Astraeus in Trial of the Spheres. This includes if he takes recurring damage over time effects, like from Poison or Fire Elf. If his shield is destroyed with spells like Pierce that do no damage to him, the shield stays off (until you hit him again with damage). He continues to do this until you kill his minions. When he's alone, he stops shielding himself, and then starts doing his star damage to your group every round. As a pyromancer, the downside to Kaizoku is... he's fire. You put a prism on? A prism is a trap and is dispelled for free. You can try for some off school damage, or you can just build up your most powerful hit and hit him as hard as you can (provided his minions are already gone or you've used a treasure card pierce on him first). Though casting traps and negative charms directly on him get dispelled, those from creature effects stay on. This is why efreet is nice. However, that your -90% attack debuff on him will be used up on his free star attack, so it's not as good as you might hope.
UPDATE: I noticed if someone has a shield on them, during his star attack he will attack that one, destroy their shields, but not use the star attack on others. This happened several times, but not sure if he does this every time.
I run through pagoda with my Deck of Devouring Flame set-up. It's got something like the following:
4 x Gargantuan
4 x Empowerment
4 x Fireblade
2 x Elemental Blade
4 x Meteor Strike
3 x Fire Dragon
2 x Rain of Fire
1 x Efreet
2 x Fairy
2 x Fire Prism
1 x Fireblade (item card)
1 x Fire Trap (item card)
5 x Wand Attack (120 ice damage)
My general play order (saying things go right):
Turn 1 Empowerment
Turn 2 Fire Blade
Turn 3 Gargantuan + Fire Dragon
Sometimes I get turn 1 Gargantuan + Meteor Strike.
Sometimes I get turn 3 or turn 4 Gargantuan + Rain of Fire with either one or two blades on it.
If I'm concentrating on taking out the boss, I'll discard through, putting three blades on myself, and pairing Gargantuan with either Fire Dragon or hopefully an Efreet. Make sure to dispell any shields before hitting if you can help it. Wand attacks or treasure card spells will do that for you, depending upon the boss.