IIRC, they did not.

 

How long did Hermione spend petrified in book 2?
Assuming that Hermione took extra time to sleep for the extra time in book 3, how much extra time did she gain?

 

While "petrified" traditionally refers to being turned to stone, Mr Filch thought Mrs Norris was dead, which implied that she was indistinguishable from what things normally look like when they're dead i.e. not stone.

 

Were the limbs frozen in motion or were they limp, and thus could be moved about, during the petrification?

 

Frozen in the motion I think. There was a scene in the 2nd book where Harry tries to take a page from Hermionie's hand without ripping it.

 

Doesn't the word petrification kind of give it away?

 

I dunno about you but if I saw someone turned to stone I'd think they were dead. Petrification to me (someone without actual wizardly knowledge) basically means 'dead, but with some extra bells and whistles'.

I doubt someone like Filch would have any reason to know that being literally turned to stone is a reversible condition.

 

In most cases, petrification also means being literally turned into stone and not just immobilization, as far as magic is involved (outside of HP, that is), and the lack of which made me question whether the body was susceptible to having its limbs moved about, provided some magical 'oil' might be used to spring it up.

 

They learn magic levitation in first class.

 

They don't, actually. They start Wingardium Leviosa at Halloween (troll incident, remember?), after two months of classes.

 

I remember having the American edition of the first book, and the blurb for the second at the end of it mentioned students getting turned into stone. I am positive of this.

 

Right, first year, not class. My memory is so bad :facepalm :facepalm :facepalm :facepalm :facepalm :facepalm

 

American editions aren't the go to for canon though. Don't they call the Philosopher's Stone the Sorceror's Stone?

 

They do, but I was of the opinion that that was the only difference. I bought the first book in the US, and the rest were all Bloomsbury editions for me.

 

For differences, look here.

 

Why don't students use magic to make Filch forget they were doing something they shouldn't?

 

Because it's wrong.

 

That's a bit advanced for students, don't you think?

 

What of it?

They do seem to hand out Memory Charms like Snickers, or else they couldn't manage to keep the Wizarding World hidden in the age of cameras being stuck in every nook and cranny (the epilogue takes place in 2017).

 

Memory charms are very advanced spells, and It'd take a NEWT lv student, minimum to do them. Most students who focus that much on schoolwork don't do stuff that would aggravate Filch anyway (If you want to reference the dragon attack in Fantastic Beasts as a counterpoint, remember that that was an extremely rare occurrence). Plus, Dumbledore at the very least can detect magic, and it's plausible that there are spells to detect memory charms.
Also, most students probably wouldn't think of obliviating him, and mind-raping a member of staff should have a punishment orders of magnitude worse than replacing bludgers with enlarged/charmed dungbombs or something.