With that party I would dump Aerie, especially if you are going to get Imoen later (mage/thief). Aerie is a good cleric/mage, but with Edwin and later Imoen, you don't really need another mage. Like stated above, Jaheira has some cool spells that Aerie cannot get.
Also, if you don't mind having a good/evil mixed party, I would think about Viconia, she is a pretty good cleric!
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