Lenient? Not only turning him into a woman for all time, but taking his magic away? There is no way Edwina would be working as a barmaid if she could still function as a wizard. As far as I'm concerned, depriving a mage of his magic is a punishment far worse than death, it's much like poking out the eyes of an artist, or cutting the hands off a musician. No, it wasn't lenient. It was torture, lifelong torture. At least I won't do anything worse to Elminster than temporary inconvenience and humiliation.
Not to mention that Mystra has *no* business depriving a mage of his magic unless he threatens the very fabric of the Weave itself, according to official sourcebook material. Attacking her pet toy boy doesn't count as such in my book. If she does such a thing, she breaks her own rules.
And no, I still disagree about Jaheira. Elminster isn't obliged to go fight her foes for her, but he deliberately withheld the truth from her, and as I see it, let her go through mental anguish for no apparant reason. To me, he comes across as somebody who manipulates people for kicks. It wouldn't have cost him any trouble whatsoever to tell her the truth, but he has to make her 'prove her worth' or whatever.
On Edwin: But it doesn't specifically say that Elminster did, in fact, take his magic away. Not to mention the fact that I don't recall Elminster even having the POWER to take anyone's magic away (Elminster is against that anyway, he believes in spreading the use of magic and accepts that many magic-users are evil--In El in Hell he attacks the Simbul because she was killing Red Wizards wantonly, in fact). I know it seems like a lame thing to say, but the circumstances of the whole thing are not really explained. Who knows why Edwin is working as a barmaid (or tavern owner, or whatever)? Maybe the Bioware designers just wanted a cheap laugh at his expense?
I would advise against blaming it on Elminster, because I seriously don't recall him having the power to take anyone's magic away--I know there are some terrible curses that can do this, but they would only be used if one's use of magic threatened the Weave--Elminster wouldn't have a person stripped of magic just because they attacked him.
Jaheira: I don't get how Elminster was "withholding the truth" from Jaheira, as you say. Contrary to popular belief, Elminster does not know everything, and while he may have known something was "going on", how do you know what the extent of his knowledge about Galvary and his friends was??? He probably felt that the situation would play itself out, as well--he wasn't trying to get Jaheira to "prove her worth" to her--IMO he already thought her a worthy person, or he wouldn't have personally given her a Harper Pin. As Mikka said, that isn't something that usually happens--he doesn't run the Harpers and does not ordinarily give out Pins.
If he did know, well, maybe he felt that she could learn something from it all. Yes, she went through some anguish, but most growing and learning comes through pain, not pleasure, happiness, or complacency. Even if this was the case, I still believe Elminster thought her a worthy person. This isn't "testing" her, it's just letting what will be, be.