The biggest issue we have is the part of Costa being cremated. They needed to explain more as to why, as that is against the Greek Orthodox faiths teachings on death and burial. Especially since we know Costa was an Orthodox Christian, as the previous movies portrayed. And a wedding with no Greek Orthodox priest? They did not show the wedding? As she may have been an Orthodox Christian refuge from Syria since almost all of them are? I agree with the other comments that the LGBT element wasn't necessary to the storyline at all.
