these two are so autism and I can thoroughly explain why
in season 1, James always sits in a forward position with his hands in his lap.
James also plans out things ahead of time, much like a person with autism likes a consistent schedule in their day.
Early season one James also has an unhealthy hyperfixation in murder. According to him, he has killed multiple animals, and he contemplates which position he should kill Alyssa.
In both season one and two, Alyssa is known for her harsh and cold tone, even when she's being genuine with others. Alyssa struggles with getting along with others due to how cold she tends to be.
Alyssa is also fully aware that she is different from others, as she often quotes that she thinks "there's something wrong with [her]."
That's about all the traits I can name of the top of my head haha yeah