I've heard two opinions among EO regarding this issue.
One priest I know claims that there would be 2 popes of Alexandria. I opposed to this and said "One bishop for one see (city)" (yeah, I know nowadays, especially in USA and Western Europe it's so difficult to reach this situation) but he says it in today's world it wouldn't be problem. When I was watching the enthronement of the new Coptic pope, I saw it could work, but I think for the rest of Orthodox world and especially for non-Orthodox it would be "clearer" when there was one pope of Alexandria.
The second opinion is that Greeks should concede to the cradle Orthodox nations of these territories - Orientals. I think in Egypt it's quite obvious, but as for Antioch, I don't know - EO Antiochian Patriarchate is very active also in Syrian and Lebanon, not like EO Alexandrian Patriarchate, that in Egypt has few believers, but carries on mission in other African countries. For sure, the synods should consist of bishops of two rites, parishes also should have (generally) one rite. I think the best option for the division of 2 rites would be at the parish level, not diocesan - too many "layers". And the priests of one patriarchate should know both rites.