It is realistic in the sense that it is not impossible for someone to be like this.
However, this sort of person is extremely rare and is the combination of several different character, mental and physical traits all at once.
My daughter is autistic and she has the following out of your list:
•Eidetic memory (she remembers things from years ago, a big deal when you are 3)
•Obsessive compulsive about schedule (pretty standard for autistics)
•"Random" fears (she is terrified of some loud noises, dogs etc).
•Minimal interest in people (she lives in her own world a lot of the time but interacts happily with alter egos)
However, some of these are typical for a 3 year old anyway.
I have mild autism and I had several of these traits but have learned coping strategies. I used to have very good memory for things I had heard and could repeat some conversations from years previously word for word, if I watched a film a few times I pretty much knew the script etc. This has lessened now - now that it would be very useful.