Hmm not really. Though it would be fairly easy to nerf all the HLAs MAGICFIRE damage to simply FIRE damage and stuff like that. I suppose you want something that does damage but doesn't actually kill the enemy? Or do you mean making the damage of SpellNerf do non-lethal damage to the mage? If so, I'm not really interested in effects that just do damage as a result of using spells like Time-Stop - too easy to work around. Just Heal / Regen / Drink Potion and what not...
I also looked up briefly the Balthazar bit in Ascension, it seems they just checked for him being alive to show that he is about. That means InParty probably wouldn't work. InMyArea checks should work fine, though you may experience occasional oddities of NPCs interjecting across impossible distances.
The summoning idea isn't with that much merit, since most conversations are triggered by Banters which run in the background, hence have to be addressed
That being said though, the summoning should be achievable by using a single script to summon other NPCs along to Follow the PC. I doubt they'll actually be IN the party, but it should be doable.