We all know that Rei is passed so he can be a variable for the MIND.

After listening for xth time to the audiobook and hearing the description of Lennon... I have to wonder if all Atypicals are similar. Something about them, whether physically, mentally, or emotionally, is outside the norm compared to most CAD users.

We know that Rei has his genetic condition.

We also know that Lennon continues to hold onto some chubbiness

And both of them are much shorter than the average user.

This makes me wonder about Aria's brother and Dent herself. What is it that sets them apart that got them assigned an A-type device? Because I'm sure that device assignment isn't random. We're practically told as much by the Mind during the 3rd test.