I read it as Snape being happy that Voldemort offered Lily an out: his deal with Voldemort must have been "please let Lily live and I'll do anything". The memory confirms the story that Voldemort gave Lily an option out ("stand aside"). So he considers Voldemort to have held up his side of the bargain.
This interpretation does not bode well for the Dumbledore-Snape alliance (which already seemed to be in bad shape in MoR)
Harry should just threaten to destroy Azkaban, and say that Dumbledore can testify that he has the power to do it.
The easier solution there is to do something to Harry, not let off a filthy mud-blood murderer to satisfy a childish terrorist's demands...
And Mad Eye is Bruce Schneier.
Chapter 61: 'There was another pause, and then Madam Bones's voice said, "I have information which I learned four hours into the future, Albus. Do you still want it?"'
This seems like a useless question. A bit of information was already conveyed representing the fact that Amelia Bones was 4 hours into the future & found some information that would be useful to Dumbledore. Is this not sufficient information transfer in and of itself to prevent Dumbledore traveling backwards?
Sorry if I'm confused, but reasoning about time is hard, and my diagrams are not as helpful as Snape's and Dumbledore's.
"Is this not sufficient information transfer in and of itself to prevent Dumbledore traveling backwards?"
Obviously it is not. I'm sure that Harry would find it ludicrous that such a rule exists permitting the transfer of this one bit of information but not the rest of it... but neither Amelia nor Dumbledore think in terms of "bits".
Btw this "6-hours" window? Though I don't expect it, it'd be hilarious if in-story this had anything to do with the infamous "TimeCube" ramblings. Something like "Gene Ray was once an Unspeakable that went insane trying to figure out the mysteries underpinning the 6-hours rule.".
I think a fossilized hominid might have worse than average chance of having no living descendants too: To be fossilized they have to undergo a fossilization event, which is probably correlated with disaster: and given that ancient human did not stray far from their genetic siblings (and progeny) this probably indicates a high chance of that disaster affecting their progeny. I certainly wouldn't rely on it.
Nevertheless, given my cultural heuristic for what counts as most important, it would probably be father (in terms of how much various cultures put a value on either the father or the mother), or most recognized powerful ancestor (Salazar Slytherin in this case).
I think Voldemort would have been staggeringly stupid NOT to have kept a remnant of his father's body given how much blood magic requires these types of ingredients.
This is unrelated to the current plot, but rather a more general thought: We know Severus is the most accomplished occlumens in the world. Might he also be the most accomplished legilimens as well? It seems that Severus, being Voldemort's spy who spends inordinate amounts of time under Dumbledore's command, would natually come under the Dark Lord's suspicions, prompting plenty of sessions of eye-staring where Voldemort verifies his allegience. Severus, of course, passes all these checks, but could he not also be legilimensing Voldemort at the same time? If...
While I agree that this might be the case, there is a logical defense for the case where Harry is non-Voldemort. Consider, if you were Voldemort hiding horcruxes. Where would you put them?
Now if you are not very smart, you would probably put up some protections, and you will expect the hero to try to break them. If you were smarter, there would be some feints and double feints and deceptions involved in the process. But if you were very smart, you would go for the hardest locations, as Harry named. These might represent a kind of "fixed point" of...
It's debatable whether Heisenberg did the former, causing the mistaken experiment results that led the Nazi atomic program to conclude that a bomb wasn't viable. See http://en.wikipedia.org/wiki/Copenhagen_(play) for scientific entertainment (there's a good BBC movie about this starring Daniel Craig as Werner Heisenberg)