I always stay in my ECV given a choice, especially where there are stairs so I totally understand. CP has accessible spots spread across the theatre so that after you are set in place your family can sit in the seats by you.
Enjoy!
If you absolutely want to see the show, do a dining package.Keep in mind those with Candlelight dining packages have the first opportunity with scooters or wheelchairs for available spots. They have a separate line for the show.