You couldn’t fully write the play around them if you wanted to to put it on reliably, but you could probably take some interesting shortcuts. “Oh, the protagonist is supposed to wake up from a nightmare in a nervous sweat? Okay, cut to black while they’re in the nightmare scene; moments later, open the lights on another part of the stage where the identical twin actor is fully dressed in pajamas and wakes up in bed.”
As long as you juggled this right, you could have a character that teleports and changes costumes instantly. I’ve never done theatre, but this sounds versatile.
Nothing in your example requires two actors.
It’s not that it requires two (did you mean twin?) actors; that’s what I meant about “not fully writing the play around them”. The example here has someone wake up in a different place than they just were a split second ago, and the effect is really convincing because they’re twins. You could make this work without twins, but it’s a neat bit of trickery that’s easy and seamless because there are twins.