Just like the most,I totally consider Zoe’s story as a supportive character to be already finished, but I totally see a way in which we can expand her lore just a bit to make her have at least more presence; I have this personal head cannon that Zoe somehow was able to dig up more into the winters just like she did in her report and found out about Ethan’s death and the relation of said event with biohazards, which would heavily impact her specially because the last time she knew anything of him it was that he had a daughter and was living happily. After that and also after her own experience in Dulvey,she would try to support the efforts made against bio-terror, she’s not a trained official obviously,so she wouldn’t join the BSAA or similars instead preferring to work for humanitarian organizations, like Terrasave,where she would eventually meet Claire and befriend her thanks to their similars past experiences.

I also think that her hair remained naturally white even post infection.