#3 Could be fired by the end of 2019: Zack Ryder

The man who would eventually become known as the Long Island Iced Z has been in the WWE for a very long time. He first cut his teeth in the developmental territory Ohio Valley Wrestling in 2005. Ryder was groomed for the tag team ranks, a role he would eventually excel at.
Ryder made his official WWE debut in 2006 on the ECW brand, where he and Curt Hawkins pretended to be related as the Major Brothers. The Major Brothers only had a minor impact, and were quickly shuffled off to become Edge wannabes. They helped the Rated R Superstar win many matches as the Edgeheads.
Breaking Vince Russo and Jim Cornette update HERE.
When Hawkins was let go by the company, Ryder developed his Long Island Iced Z character based on Jersey Shore. He used his podcast and social media to leverage his way to becoming a bigger star with WWE, but his momentum seems to have fizzled in recent years.
Why he might be fired by the end of 2015: Ryder has been with the WWE for over a decade, and every time it seems like he might break out he ends up back in the lower to mid-card. Sooner or later WWE might cut their losses with him.