Ok, I am sort of confused. I've only read the manga. I keep trying to sort everything out in my head but some peices just dont fit.
The death of Light came from the defeat from N. N had access to the deathnote. In previous chapters he inquired on the rules of the deathnote and seemed to be conspiring. If you noticed at the end N tells them exactly what M-Kira was going to do. At that point is it not reasonable to say that Near wrote down his name in the deathnote prior to him going there. Controling him so that everything would unfold as Near wanted. Maybe even to the extent of controlling M. Its hard to say.
I don't think the girl from the cult is anyone special. I think that Kira leaves a mark for the rest of time though. It's to say, he formed a religion based off of his ideals. Which in a sense is what he wanted to accomplish but with the whole world. Now, only those that believe the same can continue this way. N wins in the form that everyone has the choice. I think Light deserved to die the way he did. He doesn't need to be a shinigami. His legend will live on and it will always be in the back of everyones mind.
What would Kira do?