"Not doing anything to help the Dark Lord" is a difficult bar to measure. If they were indeed powerful artifacts that they were going to take with them to fight him, and they (as inexperienced teens, at least in Scrimgeour's view) were very likely to get killed while doing so, then handing over the artifacts to them would be indirectly handing them to the Dark Lord.

That may not be evidence of actually knowing that he lied, but just believing that he did for other reasons. The request to speak face-to-face is quite likely to enable him to use Legilimency to be certain.

All of the books in the series have "hosting" as a concept, which is the borrowing of a host body by an alien mind; in earlier books this required the host to be brain-dead, but that was later relaxed to requiring a willing/voluntary host. This particular book extends this practice to an involuntary one as well.

But that would just be speculation...

While this is not the one you're asking about, this premise sounds quite similar to the current-season anime I've Been Killing Slimes For 300 Years And Maxed Out My Level .

Given how much water content would be in any Earth food, it seems unlikely the aliens would want to purchase anything from him anyway.

Yes. Perhaps I misread what you said combined with @DarrelHoffman's subsequent comment. I thought you were implying that he remembered the time machine appearing in the past on that date as well. Which at least should not be the case in the original timeline. I think we're in agreement now that this is not what you were saying. :)

BttF is shown to subscribe to the alternate-timelines theory of time travel, so the Doc in Marty's original future would not remember encountering Marty and the time machine in the past (and thus this cannot be the catalyst @DevSolar suggests). However, the Doc in the future that Marty returned to would, which explains what happens towards the end of the movie.

Tenure extension was a gradually increasing prize. The losers of most earlier rounds were simply deported, but about halfway through the loser got a one year extension (which meant they could only stay for one year, unless they won more at the following Tourney -- as soon as they enter any remaining years they had are forfeited). Then two years for the next round's loser, then four, etc. The loser of the second-to-last round received 20 years, the loser of the last round received lifetime (presumably unless they entered another Tourney), and the winner received Citizenship.

There's some kind of missing text or formatting error after "it would suggest the".

@xDaizu Such is not necessary, assuming that the path between the two Discs (or more correctly, where the original Disc was and where A'tuin's Disc will be) is straight. (Or mostly so, since there will be some perturbation from passing stars or other turtles, even at a distance).

@mg30rg Presumably the troll, being something that has a larger mass than a water droplet (which easily fragments), had a higher terminal velocity as a result and was able to overcome the other turtle's gravity and achieve escape velocity. Once in regular space he would continue travelling at that velocity until he reached A'tuin's Disc. Although that might require that the atmosphere decreases before gravity starts bending, in order to increase velocity while falling; since gravity also acts on atmosphere, that's another aspect that needs explaining.