Though it keeps getting repeated, it is simply not the case that the upcoming council is the first pan-Orthodox synod in 1200 years. There have been numerous pan-Orthodox synods in the past 1000 years: https://en.wikipedia.org/wiki/Eastern_Orthodox_Church#Ecumenical_councils

And Patriarch Bartholomew is not at all like a Pope of the East. He is the first in the Diptychs, and so when present at a Liturgy or a pan-Orthodox Synod would have the right to preside. He has no authority per se over the Russian Orthodox Church, which is itself the majority of the Orthodox Church. The Russian Church has long had its own direct relations with other Christian groups, and so which this meeting would be a first in the sense that the Patriarch will meet the Pope in person for the first time, it is certainly not the first time that official contacts have been made.