Adding to my previous prediction comment:

Predictions:

Harry can resist the Imperius (if it were to be cast on him). 90%

Quirrell enchanted Harry's pouch so that Quirrell can enter and leave on his own in his Animagus form, and there is no mention of those enchantments being removed after leaving Azkaban. This fact will become plot-relevant at some point in the final arc. 75%

Some magical effect was previously preventing / discouraging Harry from figuring out that Quirrell is Voldemort. 65%

Speculations:

The True Patronus appears to have more intelligence than Patronus 1.0. Animal Patronuses can send messages in their caster’s voice, carry replies back, answer yes/no questions, and lead their casters to people / other Patronuses they can find, but only Harry’s Patronus has shown any concern for who might overhear it and spoken without being commanded to by its caster (see chapter 56 for examples of all of these). Notice that Dumbledore wouldn’t expect a Patronus to warn its caster of another Patronus seeking it (otherwise using his Patronus to find an intruder would just tip the intruder off) and Harry doesn’t expect animal Patronuses to show any discretion about who might be listening (chapter 97). Harry’s Patronus is also the only one we see that can be willed to take a form other than its initial one (chapter 100).

If Harry becomes an Animagus, what sort of form would he have? Animagi who can cast corporeal Patronuses normally use the same species for both (for example, McGonagall), but Harry’s Patronus is human. Does this mean he would become a Metamorphagus?

Observations:

A Catalog of the Snippets of Later Events:

Chapter 1: (event not found as of Chapter 104)

Beneath the moonlight glints a tiny fragment of silver, a fraction of a line... (black robes, falling) ...blood spills out in litres, and someone screams a word.

Chapter 2: (event found in Chapter 90)

"Of course it was my fault. There's no one else here who could be responsible for anything."

Chapter 3: (event found a few lines later in the same chapter)

"But then the question is - who?"

Chapter 4: (event found in Chapter 6)

"World domination is such an ugly phrase. I prefer to call it world optimisation."

Chapter 5: (event found in Chapter 87)

"It would've required a supernatural intervention for him to have your morality given his environment."

Chapter 6: (event found near the end of the same chapter)

You think your day was surreal? Try mine.

Chapter 7: (event found in the middle of the same chapter)

"Your dad is almost as awesome as my dad."

Chapter 8: (event found about one-third of the way through the same chapter)

"Allow me to warn you that challenging my ingenuity is a dangerous sort of project, and may tend to make your life a lot more surreal."

Chapter 9: (event found about two-thirds of the way through the same chapter)

You never did know what tiny event might upset the course of your master plan.

Chapter 12: (event found near the end of the same chapter)

"Wonder what's wrong with him."

Chapter 13: (event found near the middle of the same chapter)

"That's one of the most obvious riddles I've ever heard."

Chapter 14: (event found about two-thirds of the way through the same chapter)

There were mysterious questions, but a mysterious answer was a contradiction in terms.

Chapter 15: (event found near the end of the same chapter)

"I'm sure I'll find the time somewhere."

Chapter 16: (event found near the end of the same chapter)

I'm not a psychopath, I'm just very creative.

Chapter 17: (event found near the middle of the same chapter)

"You start to see the pattern, hear the rhythm of the world."

Chapter 18: (event found near the middle of the same chapter)

"That does sound like the sort of thing I would do, doesn't it?"