Thunderbird was one of the “all-new” X-men introduced in the mid-1970s in Giant Sized X-men 1 (along with Colossus, Storm, Nightcrawler - also when Wolverine and Banshee joined, although they had appeared previously in Marvel comics) and then Uncanny X-men 94, but only survived until issue the following issue, 95. In the 90s his brother was introduced, however, and he has identical powers and was around ever since, largely with the New Mutants/X-Force. He was also in the movie Days of Future Past.
Polaris has been around since the 1960s, in various X-men comics. Long-time girlfriend of Alex Summers, aka Havok. She’s got the usual convoluted history, with lots of terrible shifts (into insanity, into a daughter of Magneto/then not/then yes, etc.)
Blink was also in Days of Future Past and was a character introduced in Generation X in the mid-90s (Generation X was essentially a younger version of the New Mutants, after the New Mutant characters had aged into other roles in the core X-men or X-force). Blink was killed off in the comics immediately, but brought back in various alternate-reality stories.
Others are new. Looks like a modern Generation X/New Mutants, etc. Since there actually is a New Mutants movie in the works, this probably won’t use characters that overlap with that movie.