We are confused at the moment too. When Thea was originally created she was a deaf character, when she has returned after many years she isn't but is replacing Maddie who spent years pretending to be deaf because Thea was originally and Kit needed access to hearing aids to control the volume of the world outside. (due to extreme sound sensitivity)
To complicate matters further the physical body no longer has the degree of physical impairment that Maddie originally had but still we have to present at Maddies level of disability to some people. Our 'system' is controlled by someone who was severely autistic as a child and has severe 'Exposure Anxiety' - meaning she is unable to learn directly from people or do things (any action even as simple as walking, eating or speaking) with others watching, so consequently any alters have some degree of autism, although presenting much milder publicly than Kit.
Maddie had it but was in complete denial of it, because she got treated better as a wheelchair user than someone with a mental health problem so hid it.
Thea used deafness to disguise Kit's struggle to understand people in the early days when she needed to venture into the adult world via college and the workplace.
Consequently we have reached nearly 50 and are not sure who we are anymore! Kit recently felt she wanted to come out' as herself and have a life as herself for remainder of the body's years, but after attempting it still really struggles with anything unexpected triggering panic. so she is currently working on a new persona/alter to push to the front who more accurately represents the physical body as it is now. We have no idea whether this will work or not to give us a better sense of identity!