I don't think a 20th level DW character could ever be classified as a demigod. Or maybe it can?

and, you can always create and learn custom spells through ritual.

hirelings are (also) a player's resource, so as such, they are vulnerable to the gm's move "use up their resources". You make this move as hard as the rules allow it (so is a soft move unless you have a golden opportunity - that is, a player rolls a 6- on a move involving the hireling or the party deliberately ignores a threat menacing the hireling).

All of this to say that killing a hireling is just using up their resources, very hard.

Isn't it rather more relevant what Conan or Gimli used?

yes, it is.

are the longsword, the battleaxe and the flail two-handed weapons despite the lack of the Two-Handed tag in the weapon list?

no, they are not. I always thought this has to be related to the historical absence of 2 handed weapons in medieval warfare, with the exception of polearms (which in fact are present in DW under the name of halberd). However, it's been said plenty of times: if you need to have a difference between one and two handed swords, just apply some +1 damage, x2 weight, x2 coin on the latter, and that's all. You should always expand the equipment list with whatever you would need in your game. It's not that there are only those four poisons in the world...

my 2 cents (and I don't know if someone else said something similar; if yes, then forgive my laziness):
in my games, that the druid could fly unnoticed above every obstacle was of a narrow utility. The rest of the party had to subvert the obstacle anyway. It's not like the thief that disarms a trap for everyone or a magic ritual that teleports everyone at once.

I remember one time when the druid flew ahead to be sure that there were some survivors beyond a wall of zombies, but then she came back and fought the zombies together with the rest of the party. Another time, she pursued a fleeting boss underwater, but when she reached him, she couldn't beat him all alone. And while she had an easy time going down a pit full of prisoners and also helped carrying one in the form of an eagle, the rest of the party had to consume an obscene amount of rope to get down, take the prisoners, and come back upstairs.

that's going to be included in my games.

yeah, it's written that you can roll on the table, not that you have to. I never used that table. Strangely enough, it's very rare that characters in my home group go on adventures for money, so treasures are not that important, and if they are, it's something like: the sword of cosmic balance lays at the center of the magnificent old king's treasure. But beware: anyone that touches even one copper coin in his forgotten tomb will be destroyed by the mighty guardians of stone!