Yes, Zara's been a surprise but she's been in a very turbulent relationship with Sam Thompson for years which has been highly-publicized in the press and had a huge storyline based on this relationship when they were on Made in Chelsea thus she kept herself in the limelight after appearing on Love Island. Without those factors, I doubt she'd be successful as she is now. However, I'm pleased for her as she seems like a lovely girl!
Regarding, the other contestants, I think they're going to be a few big, big surprises in terms of post-Love Island success. I predict a few people - those who didn't stay in the villa for long or didn't have a good edit on the show or those who don't do much now but as time goes on, will start to slowly carve out a career in showbiz - will do very well in the future! Keep your eyes peeled!