React is an incredibly safe bet as well. Facebook is so heavily invested in it that they have multiple engineers working on it full-time. Furthermore, since they actually use the framework, any breaking changes are required to have a clear migration path. They published a blog post [0] explaining their strategy for how they intend to handle version transitions, which I consider incredibly developer-friendly. Look at angular 1.x for an example of a horribly handled transition.
[0] https://facebook.github.io/react/blog/2016/02/19/new-version...
Understand that good programmers are kind of hard to find, but okay programmers with experience in XYZ stack are not. Why? Because any reasonably competent programmer can become familiar with a new framework or library in about a week or two. Being able to separate the signal from the noise, and architecture an application well within that framework? That's what you're looking for. The tools themselves aren't that important.
Anyone who has a solid grasp of (modern) JavaScript will be fine with any front end tech stack.
Ideally you would get a grasp of what they need to do and some idea on how they need to do it. If you don't then you should hire someone that does, or who you can feel almost absolute confidence in. Then let them do the hiring.
Just my two cents.
Many people spend X hours a day obsessing about whether css-turd-polish.io is better than Sassy.js v4. If you spend those hours working on something productive, you're automatically ahead.
The framework churn is increasingly a perpetual motion machine for conference talks. Don't go to conferences and you won't feel like you're missing anything.