Health,
1. Who are these anonymous “Litvish Poskim & the Brisker Poskim”? Are they the “gedolim shlita” who sign pashkevilim?
2. RZ does not have “that many Rabbis”? What about, Rav Kalischer, the Netzviv, Rav Kook, Rav Uziel, Rav Meir Simcha, Rav Soloveichik, Rav Avraham Shapira, Rav Goren, Rav Tzvi Yehuda and Rav Mordechai Elaihu? You can add Rav Ovadia, who called himselfa Zionist. Rav Shlomo Zalman Auerbach who said that when he wanted to go to kivrei tzaddikim he went to the military cemetery on Har Herzl and Rav Asher Weiss paskens shailot from IDF officers so maybe they can also be considered Zionists.
3. I think that it is obvious that this only holds when there is a discussion and vote. Otherwise how do we know? Moreover, there is the question of who is included. This was the Rema’s reason for rejecting the Mechaber’s two out of three (Rambam, Rif and Rosh) sheeta. BTW, sometimes we pasken like a yachid. For example, we often pasken like Rabbi Yossi against Chachmim because his reasoning was with him (nimuuko imo).