Necro factions to preserve while leveling?

[aGenda]

This question is mostly for classic and kunark era. Are there any areas a necro ought to avoid while leveling that would cause faction related issues when trying to quest later (aside from killing your own starting city factions)?

For example, it is convenient for a new gnome necro to xp in crushbone, which will lower neriak guard factions, but does that matter? You could still invis to the bank or spell vendors if you needed to go to neriak? I know part of the necro epic involves handing in an item to a dark elf npc but not sure if it would be on that faction or not.

Also if you worship Cazic and then kill Cazic in PoF does that screw anything up?