[SixOfSpades]

Aura Cleansed: I've seen this message a few times too, but only in BG1, and only in dialogue situations like the ones described. It might be a fragment of some feature that was only half-implemented and not completely removed; for instance, the theory proposed by Legolas sounds good (when you do something bad, like robbing the Hall of Wonders, the Flaming Fist will hunt you until you pass off the merchandise and get your aura cleansed), but it is not actually in the game. However, it might have been part of the game in an earlier phase of development. For example, if you take Ragefast's Nymph to Ramazith, she warns you that it would be wise to avoid the Fist, as they would not look kindly on anyone dragging a Nymph through the city. This idea is the most plausible explanation of "Aura Cleansed" that I have yet heard.
Daer'Ragh's Aura Cleansing was not implemented, in any of the games. Even if you meet Daer'Ragh, he doesn't cast any spells. The break between spellcasting, however, WAS implemented: Get ToB and your Wizards will start drooling over Improved Alacrity.
If you're confused by Morgeurat's talking about lightning, just ignore it. That's something completely different from Aura Cleansing.

Edwin: You actually CAN have violently opposed people in your party, even all the way to the end, *IF* your Charisma is really high (as InsaneBane's is) and you don't piss either of them off by keeping a Reputation violently in opposition to their Alignment. So, yeah, Edwin will work for you.....for a while.

By the way, xanderwatts, actually giving yourself the spells listed in Gatekeeper (the ones you can't actually find in the game) may be neat, but if you play with fire, don't be surprised if you get burned.