If Wendy didn’t want anyone to know about this I wouldn’t underestimate her, she could probably kill Martha alone, in the middle of her writing a sentence.

Wendy-as-Joshua pushed Jennifer down some stairs in “The Funeral” chapter, and we see Martha also falling down some stairs before the imps grab her in the “Unlucky Clover Field” chapter, so it seems likely that Wendy pushed Martha down the stairs to initiate the attack by the orphans. Wendy may not have been the one to summon Martha away from the letter she was writing, however. That might have been someone else, even Jennifer (who apparently saw Martha fall, and saw Martha reach out to her, so we know Jennifer was around at the time).

In the Gingerbread House, right on the shelf placed on the rrom where Gregory writes his storybooks, there is his Diary.

That date of diary’s entries, are BEFORE 1930. I remember that are on 1929.

There, are a few entries talking about his son missbehavioring. Later in the entries, it’s revealed that “Joshua” went out when it was raining and catch a cough.
The entries make me believe that’s about Wendy.

I do agree the jennifer theory is probably more plausible, sadly enough..I can not remember ( for rule of rose is a very difficult game to play even replaying) and have not checked, but does hoffman not refer to Diana as a brat sometimes? for if this is true this may add a little more support, and one more question Diana was not always at the front of Hoffman’s list? (or have I just made this up in my mind..O.O’) The wendy theory is also very interesting, but as said Wendy was in control and never would have released the rabbit on her own she could have easily got one of the aristocrats to do it for her..I believe this makes either Jennifer or Diana more plausible since I believe they both at this tie would have done anything Wendy asked for, but, another question that exists if Hoffman merely saw Jennifer with the rabbit instead of letting the rabbit out of the cage (because I highly doubt Jennifer would have let the rabbit out the cage just to go chase him down) Or if he actually saw one of the orpahns releasing the rabbit in this case leaves Diana more plausible

You are the first, I think, to propose the hypothesis that Hoffman’s “that child” is Diana. An alternate hypothesis, that “that child” is Wendy, has been argued by comment-maker Lost Orphan. At present, I still favor the hypothesis that “that child” refers to Jennifer. But it is not an easy matter to settle definitively.

In “The Funeral” chapter, Hoffman scolds Jennifer: “You dirty wretch. Why are you always trying to get out of work? Can’t you do your job like all the other children?” If Hoffman thinks that “all the other children” do their jobs well, then the “that child”, of whom he complains “Every day, that child gives me a headache. Shirking her duties…” etc., would seem to be about Jennifer, as “shirking her duties” seems to match “always trying to get out of work”.

See also my blog-post: The Hoffman Boss-battle Mystery (Part 1)

Also:
Perhaps analogously (a weak argument, I admit) in Amanda’s diary, “that girl”, and each nameless “she” and “her” seems to refer to Jennifer:

[Sunday, March 2]
I don’t know what’s wrong with me.
Was it something I did?
Last month I failed.
What will happen to me this month?
Mr. Hoffman said that a new girl is coming soon.
Will I even lose to her and be all miserable?
I’m scared. I hate to think of what’s in store for me.

[Sunday. March 20]
Things are going wonderfully!
Today they called me out to the backyard.
As long as that girl is here,
I won’t ever be last! What a relief!

[Sunday, April 4]
Maybe there really is something wrong with me.
What have I done wrong?
I tattled on Mr. Hoffman as they told me to do, but I failed again.
I’m still lower class, even after that girl came.
I’m scared. I don’t know what to do.

[Sunday, April 18]
I’m as happy as can be today!
They showed me the symbol of the Aristocrats.
If I can get a red crayon,
I, too, will be one of them!
But, that girl will NEVER get a crayon.
She’s far too uncouth. In any case,
I’ll never be last again. I’m sure of it.

[Sunday, June 1]
NO NO NO NO NO NO NO NO NO NO
NO NO NO NO NO NO NO NO NO NO
Those awful things got into my mouth!
She’ll be sorry the next chance I get.
But why me again? What have I done?

[Sunday, July 27]
I HATE HER I HATE HER I HATE HER
I HATE HER I HATE HER I HATE HER
Oh my! I’ve got to sew the rags…

[Sunday, August 31]
I HATE HER I HATE HER I HATE HER
I HATE HER I HATE HER I HATE HER
Oh my! I’ve got to sew the rags…

[Sunday, September 28]
I HATE HER I HATE HER I HATE HER
I HATE HER I HATE HER I HATE HER
Oh my! I’ve got to sew the rags…

[Sunday, October 12]
Oh, why can’t they all just go to hell!
Basil, have a nap on the railroad tracks!
Fanny, take a dive off the roof!
George, I’ll hang you upside down!
Hector, get run over by a carriage!
Ida, I have some fancy poison jam for you!
Leo, walk across an open manhole.
Paul, get smothered under a great rug!
And lastly, that girl!
The Aristocrats will have their way with her!
Oh, how very delightful life is!

[Sunday, October 19]
That wretched girl will do my dirty work.
I’ll work her to the bone!
Oh, I feel wonderful today!

Every day, that child gives me a headache.
Shirking her duties, doodling on walls, making Olivia cry, etc, etc.
What a wretched child!
(Sick Bay—after boss battle, Sir Peter chapter, Hoffman’s diary)
~~~
###12 April 1930
Today, I gave that child a good scolding.
When I found out she let the rabbit escape, that was the last straw.
As I took out my pointer to punish her, she started quibbling again…
…However, she’s still young.
She gave in and apologized, so I let it go at that.
I’m such a kind, understanding teacher.”
(Sick Bay—after boss battle, Sir Peter chapter, Hoffman’s diary)

at first I thought this was supposed to be diana and that the scolding was suggestive remark, however the reaction, of her apologizing and crying seems out of character for Diana, but it is also the same way she reacted in the mermaid princess could this mark maybe the first time hoffman touched on Diana? and that it began to become a normal occurrence.

16 August 1930

Today, I was busy catching up on my work, when Clara came by to offer me a hand.
I guess my teaching paid off.
I was grateful for her kindness.
In the wee hours of the morning, she was still working, so I gently took her to bed.
I can hardly believe it. My little Clara, bless her heart, is already 16 years old.
She tells me she wants to stay at the orphanage and help with the daily chores.
Maybe I should seriously consider the offer.
Tomorrow, I’ll discuss it with Martha.”
(Headmaster’s Room, Hoffman’s diary, “Once Upon a Time”)

this is the next time we hear from hoffman…I believe maybe this is when he begins to shift his attention to diana from clara. When you think about hoffman talks about how young “that girl” is in his last entry, but in his next one he talks about how old clara haas become.

24 August 1930

This is inexcusable!
My precious koi is gone.
The children must be responsible.
I won’t stand for this.
Where is Diana?
What’s she been up to?
My opinion of her will suffer because of this.
(Headmaster’s Room, Hoffman’s diary, “Once Upon a Time”)

We then hear from hoffman again only 8 days later. This time we know he is speaking about diana because he uses her name. He also refers to her and the other kids as the children, but he singles her out for some reason I think this could easily be a reference that Diana is the kid he had been referring to her earlier. Also right after he calls clara old almost immediately compared to his once very gapped journal entries these were only 8 days apart. When this journal is written he see Hoffman molest Diana, and diana begin to cry in order to escape trouble.

I hadn’t thought about these things. If my theory were right, some students would have noticed that the adults were gone and told their parents and if their parents had investigated this, they would go to the police to tell that the adults were gone, so the police would go to the orphanage and find the bodies…

This website is amazing. This game is very rare here in Brazil.

Sorry about the errors, but I’m brazilian and I’m still learning english, so my english isn’t perfect (yet).

I agree that it is an interesting theory.

Questions that need to be considered to make it fully satisfactory:

Why is there one and only one name on the class chart for every letter of the alphabet… except for “J”, which is missing (hence neither Jennifer nor Joshua are named on the class chart). This alphabetic correspondence seems unlikely to have occurred just randomly.

How does this teaching arrangement fit in with the fact that the orphans were left alone when Mr. Hoffman, Martha, and Clara disappeared? Wouldn’t we expect outside intervention with this scenario?

Basil, Fanny and the others may be other children that bullyed Amanda and that played Wendy’s game (The Airplane thing and the Aristocrat Club), and because of this the have their own Rooms on the airplane. They don’t appear on the game because they weren’t so important to Jennifer as the others were (and they weren’t killed by Stray Dog).

At the end of the game, Jennifer says :

And so, the tragic murder of the residents of a rural orphanage was instantly bumped from the front cover of the daily newspaper to an obscure corner…
I’m sorry everyone.
You don’t deserve to be forgotten…
But I’ll remember you…

If they weren’t killed by Stray Dog, Jennifer don’t have a reason to remember them, so that’s why they don’t appear in-game but are mentioned.