Only two? It seems most celebrities are going through something like this near constantly. Or at least they are simulating it since the drama attracts more views, reinforcing the celebrity.
But as someone who has known several people diagnosed with NPD and bipolar. Kanye screams bipolar manic episode to me. The difference seems subtle until you've seen both close up.
Delusions of grandeur are a common symptom of bipolar mania. His diagnosis explains everything. If he's experiencing a manic episode now, it's hard to draw any conclusions at all about his baseline personality (which may in fact be narcissistic).
I think most narcissists only metaphorically think they're the next coming of christ, and most of them are too self-aware to say it even if they didn't.
If someone tells you they're Christ, or Napoleon, think schizophrenia or bipolar or manic-depressive before narcissism.