We saw this show for the first time in our trip last year. We'd somehow missed it in previous trips, but we were very glad we made the time for it last trip. We also went in September, and the crowds and heat were both much more bearable than previous trips in August. I don't think we waited very long for Nemo at all, just jumped in the queue, and got in in the first load of people. The only time we were standing out in the sun, was before they opened the theatre doors.
There is wheelchair accessible seating in two areas of the theatre; an area at the back, and some seats about halfway up the theatre. As has been said already, the theatre is fairly short and wide, so you won't end up in a seat too far back to see. If she can transfer out of the
ECV, and sit comfortably on their seats, it will give you slightly more choice of seating. A CM will be able to roll the ECV out of the way (in free-wheeling mode), then get it back to you at the end of the show (you might have to wait a little while for this, as they'll be fairly busy unloading the theatre.
When we went we had a slight problem with the accessible seating. I think the woman seating us was new, and hadn't quite understood all of her instructions. At first she tried to seat me next to a group of strangers, with my mother sitting a few rows back. When we explained that we'd rather like to sit together, she told us that she had to save the central benches for larger parties with wheelchairs. In the end, she sat us together, over to the far right of the audience. The seats weren't bad, but we couldn't see everything that was going on towards the back of the stage, on the right, because of the angle we were at. It also turned out that there were no large wheelchair parties coming in, so they filled those spaces up with able bodies people. This isn't me just having a pointless gripe (though I have been known to do that

), I just wanted to let you know that you may need to speak up for yourselves. If they try and seat you separately, don't be afraid to politely explain that you'd like to stay together, if at all possible.
If she has a problem being out in the sun, you might want to consider looking into the Guest Assistance Card (GAC). Though it isn't a fail-safe scheme, it can sometimes provide you with an alternative area to wait (doesn't skip the line though, of course). See the
FAQ thread for more information on this. You could also look into attaching some kind of parasol or sunshade to her ECV, but these can be unwieldy, bulky things, and can make driving more difficult.
As for restrooms, there are some just outside the theatre exit. If you need to go during the show, just go along the back walkway (you'll most likely be seated here, with the ECV), then go through the curtain, to the right of the theatre when facing the stage. I can't remember exactly where they are from there, but they should be well signed. You can look on the
park map to find other restrooms, close by.
Hope this helps a bit!
