Hai there,
1) If their memory has been wiped and they literally cannot remember something, then they could not produce that information even under the influence of Veritaserum. I've always imagined pensieves are simple places of holding, not necessarily "transporting" the memories; as in you would still have the memory in your head but it would also be accessible via the pensieve (to be shared, reviewed, etc.) Therefore in that case I would say no, that alone would not be enough.
As to the cruciatius bit, I would agree. If they cannot recall the information they cannot be expected to produce it even under the influence of veritaserum. However, if they were to have someone "commissioned" for this purpose they would have to be careful to have said person also strip the memories related to the planning of such events. (i.e. I could ask "did you have your memory altered" and if someone remembered such things then they would give themselves away.) Similarly, if one had plans to meet with said obliviator in the future to have these memories restored, that bit of information would be free game through the use of Veritaserum.
2) This is tricky, but in general I think if someone had imperiused someone to lie, then yes, they would lie. It's probably best answered on a case by case basis for the purposes of RP here on MH. Lots of variables to consider.
3) Straight from HP wiki: "Despite being the most powerful truth serum in existence, it can still be resisted through different methods, including the taking of its antidote and Occlumency." This has also been directly confirmed by JK herself (somewhere can't find the link...) Therefore, yes, occlumens can overpower the serum. This would depend on the strength/talent of the individual in question.
Interesting observations and questions ~ !
[spen]- Spenny[/spen]
