Alison twin theory

So here's one of my many theories.

Alison was killed by her twin that's now leading the "a team"

1. In the beginning of the flashback halloween episode Alison is telling the little boy a scary story. The story is about a pair of twins playing nicely while the parents are gone then one of the twins try to kill the other and the parents come home finding their dead daughter and their other daughter with a smile on her face. My guess is that this story is true. In the clip we get to see two twins that look like a "mini alison" times two which might indicate she had a twin. 

2. The story goes on with the "evil" twin ending up at an institute for people that are criminal insane, could that be the same institute that Mona was put in? In the season finale Mona says "I did everything you asked me to" could Alisons twin have asked Mona to bring them to the hospital since Alisons twin wouldnt be able to get out to them? After the story is told the girls pass by a "scary" house and the camera moves behind a car that has a future reference to the mental institution.

3. When Alison is in the shop with Jenna she gets her first text saying "Im watching you." She had just met Jenna so there's no way Jenna could have anything against Alison, she had just heard the rumours. She was new around town so she wouldn't be able to create an "a team" that fast anyway and Alison and the girls blinded her after "A" started texting her so she wouldnt have any motive. In the scene you also see "A" grabbing the mask that later on scares Alison and that cant be Noel cause he's in the frame at the same time.

4. When Alison get a package with a voodoo doll saying "Its my turn to torture you" she hides it in her room in the box that Aria later on got from Jason. Jason said he found some stuff when they moved (or something like that) when he hands it to her, this means he didnt know that box existed until they moved which means there's no way he could have told the N.A.T club that it was there besides he wasnt even there that night. 

This means somebody else must have found the box, someone with access to Alisons room, i doubt her parents created an A team against her daughter, but maybe a jealous twin? After all, her sister was the most popular girl in rosewood, living in that shadow cant be easy!

5. In an interview with Sasha who plays Alison she says that there's lots of clues in her room to look for and this is what was found. It's written originally in french (Which obviously no one can see) but I read somewhere that it says (translated to english) This is double the laughter and smiles to double, and double the trouble if you're blessed with twins. In the picture it also appears that Alison is writing something that, in the scene she hides it from Jason could it be a diary maybe? Where she writes all her secrets down? 

6. Another thing that was found on the walls is a picture of Alison, Jason and...? Why would there be a double picture of Alison?

7. When Alison is at the party mona walks up to her dressed up and Alison asks if she knows her, Mona answers "No but you will soon" thismight indicate that the A game is officially on since Mona officially is A. She quickly notices that Jenna can come in handy when she rejects Alison so she approaches Jenna, but neither one of these would have access to Alisons room while Alison is out partying maybe someone is snooping around her room? Melissa and Ian later show up at the party aswell so they couldnt have been in Alisons room either.

However there are things that doesnt add up, if Alison had a twin the four girls would've known that wouldnt they? I mean it's a small town and they were best friends, Ali was great at keeping secrets away from the the girls but people? That's a little harder to hide. 

Another theory is that Alison is alive, but that her sister tried to kill her but she got away in the last second. She ran away and created an alterego "Vivian" but things doesnt add up here either then because "Vivian" was created before Alison "died." However there is a posibility that her twin tried to kill her earlier than her "death." 

If Alison is alive other things will add up and make since, because then it explains why the "dreams" with her seem so real. In the dreams Alison is helping the girls finding out who A is, which shows that Alison isn't a bad character and this clears up any suspition of her being A. Maybe, Alison found out about her sisters plan, she was almost killed for it and had to run.

So what do you think?