Harry Potter: A Few Questions/Mysteries I Still Wonder About

I put off reading the Harry Potter book series until many years after the first book was published for a couple of no good reasons... First off, it is supposed to be a children's book (and, being 23 yrs old when Harry Potter and the Philosopher's Stone came out in 1997, I could hardly be included in that....er... age group). Second, all the overblown publicity and media hype was a bit off-putting to my anti-mainstream younger self.

As it turned out, being unfashionably late on the trend had its perk! The first 5 books were already available by the time I decided to check out this Harry Potter curiosity thingy after having caught the movie based on the second book, Harry Potter and the Chamber of Secrets, on HBO one night in December 2003. Naturally, I became instantly addicted to JK Rowling's fabulously thoughtful flight of fantasy and was very grateful that I only had to impatiently wait for the last two installments to hit the bookstore (pre-ordered both, though didn't have the leg to do the 'storm the store at precisely midnight' thingy as many other Harry Potter fans did)... While those who had caught the Potter fever before I did had to wait quite a lot longer.

Having now read the entire series a few times, however, there are a few unresolved subplots and ideas I would love to hear the answer and/or speculation to. I'm listing them below!

SPOILER ALERT!
A note of warning for those who haven't read the entire Harry Potter series! Many questions/mysteries listed below constitute pretty good plot spoilers. Unless you are one of those weirdos who like to sneak a look at the outcome of a mystery novel before reading it, you are well advised to refrain from further reading until you have finished all the books yourselves.

1. Why didn't Albus Dumbledore seem very alarmed when Hagrid told him in the opening chapter of the first book, Harry Potter and the Philosopher's Stone (Harry Potter and the Sorcerer's Stone) that he had ran into Sirius Black at the Potter House, considering that Dumbledore thought that Sirius was the Potters' secret keeper (and therefore had good reason to suspect Sirius of being Voldemort's spy)?

2. What did Moody see when he used his magical eye to identify the boggart in the closet at 12 Grimmauld Place (during book 5 of the series, Harry Potter and the Order of the Phoenix)?

In Harry Potter and the Prisoner of Azkaban, we are introduced to the boggart, a type of magical monster that basically stands in for our phobia (deepest fear). It is one of JK Rowling's many fabulous literary invention in relating real life issue/condition by way of creatively literarize it. In the words of Professor Lupin while telling his class about a boggart in a closet; "So the boggart sitting in the darkness within has not yet assumed a form. He does not yet know what will frighten the person on the other side of the door. Nobody knows what a boggart looks like when he is alone, but when I let him out, he will immediately become whatever each of us most fears." Lupin then goes on to state that it is better to not face the boggart alone, since seeing more than one person at once can confuse the monster into trying to become more than one scary thing all at once and end up looking funny.

That should rule out the possibility that Moody saw the thing that he feared the most when his magical eye spotted the boggart through the closet's wooden frame (and the floor below it). The appearance of the boggart is then not strictly in the eye of the beholder but is dependent on what the boggart sees as well as what sees it. So... what did Moody see???

3. When exactly does the Underage Trace (the charm that detects magic around an underage wizard outside of his school) break? Does it break at exactly midnight local time where the wizard is or does it break at the wizard's time of birth (if the latter, does that change if the wizard is in a different time zone from the one in which he was born?)?

4. Whatever happened to Madeye Moody's body? We know that the Death Eaters retrieved it (his magical eye was removed and put to a singularly repulsive use by Dolores Umbridge), but was the body ever found once the battle was over?

5. What did Harry do with Snape's memories after the last battle (from Harry Potter and the Deathly Hallows)? Did anyone else get to examine them?

6. In Snape's memory of when he and Lily left for Hogwarts for the first time (Harry Potter and the Deathly Hallows) her muggle parents were goggling at the Hogwarts Express and the crowd of witches and wizards. How did they get through the barrier? Was it normal for muggle parents to be allowed through the barrier then?

7. Since Voldemort's soul fragment in Harry was the source of his ability to speak parseltongue, did that ability die when that soul fragment was destroyed? (could Harry still speak parseltongue afterward?)

8. Did Albus Dumbledore, as he was forced to revisit the fight that resulted in his sister's death, see whose spell it was that killed her?

9. Harry's posit that the Elder Wand wouldn't pass to any other wizard if he died a natural death is not quite right, is it? Wasn't it made clear some chapters before that it is not necessary for the wand's owner to be killed for it to acknowledge a new master. The wand owner just has to be involuntarily disarmed or overpowered the way Dumbledore did Grindelwald and the way Draco Malfoy did Dumbledore.

10. What happened to Fawkes? Does Harry ever run into him again afterward?