Paladin and rogue in the same group - what's allowed and what's not?

[The Random NPC]

Let me Surgical Strike your entire Argument:

Book of Vile Darkness IS NOT a 3.5 rulebook.
Savage Species IS NOT a 3.5 Rulebook. also, if you already bought it, just download it.

Even if we take the "Kill fiends because they are Here." as part of the Paladin code, that simply means if the outsider does not have the Native Subtype, then the paladin should stick a blade through their head.

While they aren't 3.5, they are 3.0. And as we all know, any unupdated 3.0 book can be used within a 3.5 game.