[daplunk]

Good questions.

How about for NPCs we don't handle stats. Most systems should have generic stats that the DM can apply quite easily.

Still note down what weapons the NPC carries, race, alignment, size.

What we should definitely handle is RP (personality). I really liked how Storm King Thunder did this. Here's an example:

Roleplaying Information
As the Lord Protector ofTriboar and a secret agent of the Harpers, Darathra has sworn an oath to defend the town. She takes her duty very seriously. In addition to her gear, Darathra has an unarmored warhorse named Buster.
Ideal: "Good people should be given every chance to prosper, free of tyranny."
Bond: "I'll lay down my life to protect Triboar and its citizens."
Flaw: "I refuse to back down. Push me, and I'll push back."

Just enough information for the DM to quickly identify with the character allowing them to build on it from there.

Magic Items should be easy enough. Put in a name and description letting the DM replace them with suitable items from their system.