I'm pretty sure traps gives full Xp.
I use the trap technique against the Iron Golem in Nalia's Keep and I got the full Xp.
I'm 100% sure summoned creatures give your party the Xp too. Coz many a time my party had a tea-party while a squad of Fire Elementals and Mountain Bears are doing battle with the forces of evil.
Avatar: Pass the sugar please.
Your party has gained 2000 Xp
Jaheira: It is strange that we stand about when there is so much to do.
Your party has gained 2000Xp
Avatar: Jaheira... learn to relax. Really, sometimes I think you complain to much.
Your party has gained 2000 Xp
Avatar gained a level.
Avatar: Oooo! How lovely, I shall have to up my Hp after this cup of tea.
Fire Elemental unsummoned
Avatar: Jaheir-
Jaheira: Yes yes, I know. Summon another one... ...
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If not a Sorcerer, then a Paladin.
