Yume and Matsu were never in the same squad. Yume was in the second generation along with Karasuba. They were the only members of the disciplinary squad during that time.
Yes, Matsu (#02) was in the original disciplinary squad (first gen) along with Miya (#01), Kazehana (#03), Karasuba (#04), and Mutsu (#05). Karasuba has been a member of all three generations.
In the scene with the helicopters, she seemed to have just searched for and verified the number of enemy units. Kazehana seemed to be the one that actually destroyed them with her "Flower Whirlwind" attack.