Ending of the Play?

Vera Claythorne and Philip Lombard survive in the play, and they are innocent.

As caviar says, Vera and Lombard are innocent in the play, and both survive. The play was produced during the middle of World War II, when London (and much of the rest of England) was getting the hell bombed out of it on a pretty much nightly basis by the Germans, and Christie decided that the last thing audiences needed was a ending where everyone dies.

Actually most of these are incorrect. The identity switch angle of Lombard not being Lombard was only used for the film adaptations.

In the play, Hugo was the one who killed Cyril, assuming correctly that Vera would take the blame but get cleared of any wrongdoing at the inquest. But since she knew Hugo killed him, she didn't marry him.

Lombard did leave the natives behind in the stage play, but as he confesses after Blore has died, to Vera, he says that he left them with all the food an ammunition and set off on his own unarmed and with no food. "Once, just once, mind you, I played the hero," Lombard tells her. He then says he made it back by luck. However, after they ended up dying anyway word got out he'd abandoned them after taking all the supplies, and after initially claiming his defense, he stopped arguing it and instead started agreeing that he did abandon them with no food or weapons. "I got such a kick out of watching their faces," Lombard tells her, when she asks about him saying what he did post-gramophone record.

Vera doesn't believe him. She gets control of the gun, and when Lombard rushes her, she shoots and he falls. Then Wargrave comes out, laughing and extremely deranged. He's not at all the cool demeanor he is when Dance is talking to Vera at the end of the film. He gives a basic rundown of how he committed each murder, and about how he set up Vera to shoot Lombard.

Wargrave preps her for the noose. Vera says he can't hang her, as she didn't kill Cyril and is innocent. Wargrave, fully-deranged, doesn't care. He screams that he has to complete the rhyme and "Must have his hanging!" He gets the noose around Vera's neck and starts choking her.

At this point Lombard, who was only grazed by the bullet, recovers, picks up the gun, and shoots Wargrave dead. He makes a comment about being lucky women can't shoot straight. The play ends with Lombard saying there's another ending to the rhyme, "One little indian left all alone. We got married, and then there were none." He puts his head in the noose with Vera and kisses her as the play ends.