There are actually many places within the Zohar discussing and explaining the concept of the Erev Rav, how they were a collection of the many non-Jewish nations who came out of Egypt together with the children of Israel and mixed in with the population, for example: Zohar, Nasso 4:33, Zohar, Ki Tisa 11:59, Zohar, Ki Tisa 11:68, Zohar, Bereshit 20:228, Zohar, Bereshit 20:224, Zohar, Ki Tisa 11:60, Zohar, Bereshit 19:222, Zohar, Bereshit 21:245, Zohar, Bereshit 21:246
These citations are among those explicitly cited by the Satmar Rebbe in קונטרס על הגאולה ועל התמורה in the balance of Sief 61 which you ask about.
The Satmar Rebbe asks how can anyone actually question that there will be such Jews at the time of the redemption who will behave like this and assist Gog and his soldiers in fighting against מלך המשיח. (It is worth noting that the Zohar makes this connection to those who oppose Moshiach ben Yosef specifically.)
That there are numerous examples from Jewish history of people like this. The Satmar Rebbe even uses a telling term to describe them calling them בריון.
This expression is often translated as the Palace Guards or Palace Soldiers, but can also have a connotation of Outlaws or Rebels. (The connection to the Palace is referring to G-d’s Palace, Jerusalem. That these guards or soldiers are actually supposed to be defending and protecting Jerusalem.)
Being composed of 5 letters, it suggests that it is a compound word, which most obviously lends itself to בר יון or Greek Son. That is an allusion to Hellenized Jews, meaning assimilated to non-Jewish culture. This is in fact how Midrash describes Armilus and his followers.
The Erev Rav are that remnant of Jews in Israel and elsewhere, who have been and are cooperating with the plan from the two biologically related leaders of wealthiest nation on earth during that time. The two related leaders were President Bush 41 and 43. The primary leader of the Erev Rav in Israel during this process was Shimon Peres who was instrumental in the entire Oslo process. (For more background on Gog and Magog, see here: https://judaism.stackexchange.com/a/137627/7303) But the fallout from all of that continues even today.
There was a tradition which Moshe had from Avraham, that when the Torah would actually be given, anyone from the nations would again be given the opportunity to become a part of Israel. This is why Moshe, the paradigm for the Shepherd of faith, insisted upon bringing them out together with the children of Israel. The Zohar records that G-d told Moshe not to do this because they would be trouble for the Jewish people ultimately. This is why midrash and Zohar refer to the Erev Rav not as Bnai Yisroel בני ישראל, but your people, meaning Moshe's people (see Shemot 34:10, Devarim 3:26, 9:12) or the Congregation of Israel עדת ישראל or the Community of Israel קהילת ישראל.
So another dimension of the final redemption is that in many ways, it will parallel what took place in the first redemption from Egypt. And this would seem to include the connection of the Erev Rav, Moshe's people, no matter how small or large, with the children of Israel.
This is also how it is taught in Sefer Agra d'Kalla, parshat Ki Tisa 35 which says:
והביטו אחרי משה (שמות לג ח). תרין. דין ואידך והביטו את אשר דקרו (זכריה יב י), מה בכאן אית דרשו ליה לשבח, ואית דדרשו וכו' (קידושין ל"ג ע"ב) , ותרווייהו קשוט דהערב רב לא האמינו ואמרו מה שאמרו, כמו כן התם במשיח בן יוסף, ישראל הצדיקים יביטו ויאמרו כי הם גרמו, וישובו אל י"י ויאמינו בו, והערב רב יתחברו עם גיא המון גוג ויהיו לחרפות עמהם:
The section of Zohar you are looking for is most likely in parshat Toldot, starting on page 139a, beginning with the words:
תנן מ׳ שנה קודם קבוץ גליות לתחיית המתים כו׳
We learned that the ingathering of the exiles precedes the resurrection of the dead by forty years.
The ingathering mentioned here is the same one mentioned in the Amidah prayer. The exiles being referred to are the 288 Holy Sparks which fell into this world at the beginning of Creation.
Their ingathering is accomplished through the histalkut of the soul of Moshiach from this world. The sparks ascend with his soul back to their original source.
From that event, there are 40 years until the beginning of resurrection. 7 years from the histalkut begins the 3rd and final part of the war of Gog u’Magog. That coincided with the attack on the World Trade Center on September 11, 2001 and the war with the Taliban which began on Hoshanah Rabbah of that year and continues to this day.
It is worth pointing out that in Sief 83-91 of this same section of the Zohar, it explicitly associates the Rasha’im with Hamas and connects it to the spiritual concept of the Nachash from Gan Eden.
יְהוּדָה פָּתַח וְאָמַר, (תהילים י״א:ה׳) יְיָ צַדִּיק יִבְחָן וְרָשָׁע וְאוֹהֵב (ר"ת נחש) חָמָס שָׂנְאָה נַפְשׁוֹ.
In this context, it should also be noted that the Nachash, which brought death into the world, and its Tikkun (Moshiach) are related. That נחש and משיח share the same gematria.
