LA Times article about the role of the new female characters with an interesting hint from Kathleen Kennedy: http://www.latimes.com/entertainment/herocomplex/la-ca-hc-the-women-of-star-wars-the-force-awakens-20151206-htmlstory.html

But you won’t see Phasma tapping out after being carelessly knocked into a sarlacc pit like a wobbly toddler. Kennedy has big plans for Phasma and confirmed that the captain will carry on into the next movie. “She’s an important character, a baddie in the best sense of the word.”

Looks like Phasma will definitely survive TFA, unless KK is talking about spinoffs.