BS”D
The only thing I can suggest is to call either Rabbi Shraga Zalmanov from the Chabad Vaada leDovrei Ivrit or Bnei Akiva to see if they have any information about such a minyan.
Rabbi Zalmanov is based in Queens; 718 380 7050. If there is a shaliach in Flatbush who is involved with the Israeli community I think he would know (and I think there is but I am not sure who he is, whether he has visitors from EY as opposed to former Israelis living in Brooklyn who come to his Chabad House, and where in Flatbush he is located).
Bnei Akiva is a longshot; phone is (212) 465-9536. They don’t list anyone or anything in Brooklyn which is contrary to my (fading) recollections.
Another possibility is the Chassidish minyan factory off of Coney Island Ave (Veretsky?? – it is referred to as Rabbi ???’s shul – someone please help me out here – when I went I walked from Coney Island somewhere between J and M); so many different people pass in and out that there just may be enough visitors from EY to make the minyan you need.