Clark: Clark has been pretty solidly LG for most of his history. Well, the original GA Superman was almost the epitome of CG, and a lot of SA Superman tales had him verge on Lawful Dickish or Dickish Good, but still...
Diana: NG is certainly plausible, but the best Wondy writers have her as solidly LG and I don't think that is a coincidence. She's like a monk in that regard: she holds very firmly to her code, but her code might not seem "traditionally" lawful to observers from our society.
Bruce: Oh, I am so reminded of that Batman Alignment macro right now... personally, I see Batman as defaulting to LG, but verging on LN or NG depending on his outlook (meaning writer) of the moment. And no Rogue levels? If he wasn't CG then I'd assume that he was statted as a monk. And a higher CR than Diana? That really makes me scratch my head.
Alignment really is tricky thing. Take Hal and Ollie. Hal's political opinions are CG whereas Ollie's are LG, but their personalities are reversed.
She should look up Rama, who could be pretty believably statted as a cleric, and ask him for an atonement. (If you know what I mean, and I think you do.)
Indeed I do. He should use his mighty rod of atonement upon her. His mighty rod of atonement would drive all thoughts of Tom Tresser from her mind, and hopefully ours. I don't think that Artemis, Athena, or Hestia would like Rama's mighty rod of atonement, but I'm sure that Aphrodite, Demeter, and Hermes would. They'd even join in the ceremony, I'm sure, and Hermes would bring out his Caduceus, because he's let Diana have his Caduceus before and he knows how good she is with it.