I know that it is there for I believe most all shows. I don't know about ones like Fantasmic, but like Country Bear Jamboree, Hall of Presidents and others like these. Make sure you do get her a GAC to allow her up front seating due to the limited site. I know Sue and Cheshire have more info on these things. I also believe that if you look in the FAQ's section at the top of this forum there is a section in there with all sorts of info for those of us with different abilities. I think there is more in there about it.
Another thing that might be very helpful to you is the Passporter book called Open Mouse. It has a lot of info in there that you might find useful too.
I think you got 2 different things mixed together in your memory.
There is a screen and a handheld device available for people with deafness or hearing disabilities that puts the words to different attractions on the screen so they can see what everyone else is hearing.
There is also a fairly new device that gives a description for some attractions so that blind or vision impaired guests can hear what other people are seeing.
There is more information about both of those in post #3 of the disABILITIES FAQs thread, under Blindness. There are also a few threads linked in that area that might be helpful to you.
Most of the wheelchair seating is at the back row. Specifically, American Adventure, the Circle of Life, all the 3D movies.
A few, like Country Bears, Tiki Birds and the Festival of the Lion King, have all the wheelchair seating in the front. Some, like Laugh Floor and Turtle Talk have the wheelchair seating toward the front, with some seats in the front row.
Beauty and the Beast, Lights/Cameras/Action, the Nemo show at AK, the Bird show at AK (can't think of the name and it's too late to look it up) and Indiana Jones stunt show have seats both in the front and the back. Some people have felt having a GAC that says they need front seating is useful. Others have just told the CM what they need.
My DD does not have a major visual impairment (she does have some visual field deficits, but can't be tested to know exactly what). Between that and her OCC and ADD, we find it better to sit toward the front with her. We have just asked gotten there early and ask if it was possible. So far, we have been lucky.
If she is using a wheelchair, she may not need a GAC. It would be helpful for her to board at the wheelchair boarding area for those attractions that have a special place. That would allow her more time to get in and get settled. All the moving walkways can be slowed or stopped except for Peter Pan, Tomorrowland Transit Authority and the exit ramp of Pirates (there is an elevator you can use for Pirates). Normally, they slow the moving walkway because that is enough for most people. If she needs it slowed more or even totally stopped, just speak up.