Well, the first two pictures were the pictures of a rehearsal before one of the live shows. At the moment I can't remember precisely when it was, though.
Talking about the outfits of the final, it's true that she only performed twice, and the outfit in the last picture was one that she wore only for her introduction on stage at the beginning of the show, together with the other contestants. Then she went backstage and changed her clothes to the other outfits you posted, if I'm not wrong.