Not that is needs to be said, since you've already answered your own questions to your satisfaction, but "be a fan of the characters."

I thought about doing page references, but looking things up meant distraction from running the game, as all I have is the PDF thus far. I passed on  including the basic moves since every character should have them available, as well as the GM. It's a first draft in the layout really. I wanted to go back and make common information more clearly grouped and delineate things better, but haven't had time yet. I'm looking at borders and colored backgrounds for a second draft. Whenever I have time for that.

Or, you could let the fiction take over and preempt their rolling entirely. The move follows from the fiction, so if the evil sorcerer with counterspell is ready for them, then as soon as the wizard states, in game fiction, that they're casting a spell you respond with something like "and your bolt of magic begins to take shape, but the enemy releases arcane energy with a word and your spell dissolves into the ether."
This way they've never rolled, but you've made it very clear that this is possible. They ignored the danger in casting spells at someone who can counter them, not that they knew at the time, and you responded with a Move: Reveal and Unwelcome Truth.

Increasing the difficulty of a monster is less about mechanics and numbers, and more about using the fiction to prevent the PCs from just saying "I attack it". I mean, a demon? If you want that to be a scary fight, go on the aggressive with the fiction: force the players to respond to the terror and brutality ("as you charge the demon, necrotic power pulsates heavily from it—even getting close to it will be a challenge" or for the wizard "as you tap into the magical energies around you, you feel that the very essence of magic in the area is completely evil—manipulating it may be putting your allies and your sanity at risk.") so that they have to earn the right to hack and slash (or if they're particularly clever, gain enough of an advantage to circumvent rolling altogether.)

Going back to Middle Earth, not only did Smaug die in a single arrow, but the Witch-King of Nazgul, one of the most feared servants of evil, was slain in two blows, and Shelob, a manifestation of complete evil and gloom, was sent scampering by a blow to the stomach. In all of these situations, the hard part was not "dealing a lot of damage" but even being allowed to deal damage in the first place.

[Emphasis mine]

This is where there hasn't been as much conversation, and where I wish there were more. Granted, every situation is unique and such, but ultimately creating the fictional position in which heroes must earn the right to be effective is where I've seen people having trouble, and the general answer has been to use the fiction. It's perfect advice (and I agree with it), except that I think a lot of people coming from other systems, in which the right to be effective and dangerous to monsters comes from levels, have an, initially, harder time wrapping their heads around how to recreate that feeling and situation. But saying "use the fiction" or "fictional positioning" doesn't really help, when the real question is "how do we do that?".  There's not been much discussion of what techniques are useful or how to go about creating those situations.

We can tell players that their attacks are unable to reach the flying dragon or pass through the incorporeal wight, but when it's something powerful enough to need something extra, and yet  smaller or reachable, that's where saying that attacks simply bounce off or their weapons burst into flame and melt starts to get a little tired, especially when that seems to be the only answer to that sort of situation. It feels like a poor answer to the question of why this entity is so terrifying and powerful. There's got to be more to tell players than that their attacks are turned away by their magical armor or that their weapons melt when they strike the demon. That response gets old fast.

And it may be that something like that only takes a few iterations before people to realize they're in over their heads or that there has to be a different answer to their confrontation and that they'll shift courses and tactics at that point.
My whole point is that more conversation around this topic in particular, notably more clear and direct conversation, would be useful and helpful, especially for getting GMs out of the space where monsters are numbers and into one where they possess space within fiction and command certain interactions based on their fictional power and presence.

I love the re-skinning you've done here, taking a decidedly "Western" clothed game and turning it into something with a flair from other cultures.

Most XP is End of Session move? Wouldn't marking XP on every result of 6- provide a large chunk of that XP? Or are 6- results rarer than I think?

Surprisingly, yes. I've only run the game for one session. No one rolled a miss the entire time, and thus no one got XP for it. All of the session's XP came from the End of Session move.

It makes sense when you look at the numbers too. Rolling a 6- has a ~40% chance on 2d6, but realistically players/characters will be fictionally playing to their strengths and are more likely to have a positive modifier on most rolls, changing how often they'll roll a 6-. Even a +1 to a roll changes the chance of rolling 6- to ~30%, not to mention having higher modifiers.

Perhaps as a custom move you could allow the fighter in your game to take an additional signature weapon move as an advance, thus increasing their versatility?

That is an awesome idea, even if it's just something at the 6-10 range. I think I'm going to have to steal that for my games. I've always liked the image of the fighter as the ultimate warrior, capable of wielding any weapon, generally more efficiently than anyone else.