First things first: Kaguya and Genjutsu.
The simple reason is that they can't have it both ways: they can't be resistant to pain and then use it to cause a disturbance big enough to dispel genjutsu. They do feel pain, but their body and mind are so accustomed to it that it has no effect in "shocking" your body to produce the chakra disturbance needed to dispel genjutsu. If it worked, then basically a Kaguya user would be immune to genjutsu and not only that but would also feel distress and other physical and mental effects from protruding his bones through his flesh. Basically, they are so a costumed to pain that it no longer disturbs their chakra flow enough to release from genjutsu. And no, it wasn't "my rule".
Second, Kirin. You can use any Long Range fire technique which is at least B-Rank, directed at the sky, to induce the changes needed to use Kirin. You don't need only thunderclouds but also friction and a heated atmosphere to have enough static and electromagnetic energy around to use it. You heat the atmosphere in one turn and in your following turn you use Chidori and then finally produce the Kirin itself. In essence, 3 techniques are needed during a 2 turn time span to actually use Kirin.