If you look at the information in the disABILITIES FAQs thread about GACs (Guest Assistance Cards), I think that would be helpful to you. People have reported kind of mixed reviews about using the GAC to be seated in the front of shows. Some have had good results and some have reported better luck just telling the CM they need to sit near the front.
Another item on the disABILITIES FAQs thread that would be helpful to her would be a link to a past thread about boarding rides. You could request to be allowed to use the wheelchair boarding area - by doing that, the CMs could stop moving walkways for you, etc. There is also a link to the official WDW Guidebook for Guests with Disabilities in the disABILTIES FAQs thread. There is one specifically about visual disabilities, but it's mostly about braille.
For Fantasmic, a GAC should be helpful to sit in the front, but you'll still need to get there early. Also, bring along something to protect yourself from the mist. Part of the show involves movies projected onto a screen made of water mist. If the wind is blowing toward you, the mist can give you quite a shower. There are some things, she will notice even without being able to see. There are several sequences that involve fire - hot enough to feel. And the music from the show is very beautiful.
For Mickey's Philharmagic, she should wear the glasses, even with vision only in one eye. Without the glasses, the movie is blurry, even for people with 20/20 vision. Most of the thigs in that movie are very large, so that should help her. And, even if she can't see anything, the music is very good.