Nope! None of what I listed is in the original novel.
In the original novel:
-Sara is left at the school because she is old enough and the dad deems it proper for her to get a formal education, not because he's going off to war--he's an investor who is investing in diamond mines
-The man next door is a gentleman about the same age as her father, and is actually her father's business partner, though Sara doesn't know this until the end
-The "magic" in the room continues for a significant period of time, enough time for both Sara and Becky to be noticeably fatter and healthier, so presumably at least a few weeks; the police are never called and the 'magic' is never discovered by Miss Minchin. (miss minchin actually lets Sara return to being a pupil because the man next door, not knowing the poor child he is helping is his friend's daughter, sends her fine dresses and clothes--Minchin gets scared that she's got a rich relative somewhere and treats her as a 'charity pupil')
-the dad is dead and does not have a head injury/memory loss
-dad is dead
-Amelia has no love affair and while in the end she finally says to Minchin that she ought to have treated Sara nicer, because Sara would have repaid her kindnesses tenfold, she herself doesn't help Sara or be particularly nice to her, nor run off with anyone
-Dad is dead, Sara ends up being adopted by the gentlemen next door when he finds out that she's the friend's daughter that he has been searching for
no subject
In the original novel:
-Sara is left at the school because she is old enough and the dad deems it proper for her to get a formal education, not because he's going off to war--he's an investor who is investing in diamond mines
-The man next door is a gentleman about the same age as her father, and is actually her father's business partner, though Sara doesn't know this until the end
-The "magic" in the room continues for a significant period of time, enough time for both Sara and Becky to be noticeably fatter and healthier, so presumably at least a few weeks; the police are never called and the 'magic' is never discovered by Miss Minchin. (miss minchin actually lets Sara return to being a pupil because the man next door, not knowing the poor child he is helping is his friend's daughter, sends her fine dresses and clothes--Minchin gets scared that she's got a rich relative somewhere and treats her as a 'charity pupil')
-the dad is dead and does not have a head injury/memory loss
-dad is dead
-Amelia has no love affair and while in the end she finally says to Minchin that she ought to have treated Sara nicer, because Sara would have repaid her kindnesses tenfold, she herself doesn't help Sara or be particularly nice to her, nor run off with anyone
-Dad is dead, Sara ends up being adopted by the gentlemen next door when he finds out that she's the friend's daughter that he has been searching for