I work with 16 month olds to 3 year olds everyday. You just need to keep reminding her of what is real and what isn't. One of my 3 year old boys uses a baby doll to destroy cars. We just remind him that it is a baby and we need to play nice. It doesn't sound like she's asd, she is just being a 2 year old. Like I said lots of reminding and redirecting on your part for her! Hope everything turns out good!

My son whom is on the spectrum pretends that his dads hands are octopus. He has always done this . He even kisses the octopus good night. He has been obsessed with the plants vs zombie game for a while and he talks as he imaginary friends are mushrooms he even wanted to dress up as a mushroom for Halloween. So I made a mushroom costume. Lol They play much different and other kids look at him like he is crazy but his octopus and mushrooms make him happy. So we just tell him when he blames his mushrooms for making him mis behave that he better tell them that Owen needs to do things the correct way and they need to stop. Lol

Imagination is a good sign for kid but inability to play with a toy the "right" way isn't good.

I wouldn't worry her cooking Daniel Tiger. A lot Grimm's Fairy Tales and nursery stories are pretty dark. Hansel and Gretel are nearly cooked and eaten after being lured in a witch's gingerbread house. The kids stepmom leave the kids in the woods to die.

Pay attention to the books she's reading, and the movie's that she is watching. Something she saw or read made her think of cooking and eating Daniel Tiger. If you figure out where she got the idea of cooking and eating someone; you could talk about it with her. I'm guessing that she read or saw some horror-type narrative and is acting out what she saw or read. Also, check your web history, she may have gotten some strange ideas from websites that she visited.

If she didn't actually destroy Daniel Tiger in the process of cooking and eating him, maybe she doesn't yet understand the finality of death. She could just keep reusing her dolls to play-act with--not knowing that when someone is cooked and eaten in real life, they do not return the next day for a new game.

Also, the play-BBQ that she invited you to could be her attempt at gross-out humor.