[Conservatrix]

Good point about him (Vader) being weaker after the lava burns. Still he was not angry at Sidious at all, just angry. I would have expect him to at least fight with Sidious over Padme's death. I wondered why she looked pregnant at her funeral, that seems plausible, to make it looked like the baby (ies) died with her. Still, Vader not asking seemed weak in the story to me.

[Lunatic Fringe]

Her looking pregnant at the funeral was part of the plan. it's also why they wiped C3PO's memory. Only three people knew the truth about Luke and Leia's birth: Obi-Wan, Yoda, and Bail Organa.