I really would prefer a peaceful solution to the issue, as killing either Aldeth or Seniyad feels wrong to me. BG1NPC adds one, but only if Jaheira is in the party.
Offhand, I'm guessing that Aldeth won't be present at the Merchant League later, but I don't know if it makes a major difference. (Dudleyfix changed it so that Aldeth would betray you regardless; I forget if UB did something similar: http://www.forgottenwars.com/bg1/ar1100b.htm ).
this is the first time I play BG with Unfinished Business 1 installed. In my previous playthroughs, I have always taken Seniyad's side in his quarrel with Aldeth Sashenstar.
I was wondering if (and how!) such a choice would affect some quests, that, according to the readme, I will find in Baldur's Gate (i.e. the Sashenstar's daughter quest and the Edie Merchant's Guild quest).
Like I said, this is my first UB1 playthrough, and I have no clue what these quests actually look like. I don't mind receiving spoilers.