Often, these fanfics highlight the power dynamics between Ainz and Narberal. Since Ainz is a very powerful being, the stories may show how Narberal respects and follows his lead.
Yes, he can be considered evil. Ainz in the 'Overlord' light novel often engages in actions that are morally dubious from a human perspective. He rules his new world with an iron fist, using fear and power to subjugate others.
Yes, there could be such a fanfiction out there. The idea of crossovers between different fictional universes is quite popular, and Naruto being a fan of Ainz would create an interesting dynamic. It might involve Naruto being in awe of Ainz's power, or perhaps trying to learn from his strategies in some way.
In the manga, Albedo remains steadfast in her allegiance to Ainz. There are no instances of betrayal. The character dynamics are built on trust and loyalty.
Well, 'AA novel' is kind of an ambiguous term. Maybe it could mean a novel that's rated AA for some reason, like content or audience age. Or perhaps it's a novel written by an author with the initials AA. Without clear clarification, it's tough to say for sure.