There’s a misunderstanding here. Catholics would be refused communion in an Orthodox Church NOT for the reason that we are not “in Grace,” but simply because we don’t share the same dogmatic Faith. The Catholic Church does not admit Orthodox to communion either who don’t believe they share that dogmatic Faith with us. There’s a little premise in the allowance of a non-Catholic apostolic Christian to receive the Catholic Eucharist that perhaps you don’t seem to fully understand or appreciate. Canon law states that the non-Catholic apostolic Christian must him/herself request the Catholic Eucharist. That indicates (to me at least) that such a person actually believes there is something true about the Catholic Faith that other apostolic Christians might not accept. I have met non-Catholic apostolic Christians (Orthodox and otherwise) who don’t really understand what the schism is about, have a very simple Faith and don’t really find anything wrong with the Catholic Faith. It is such as these who will actually approach the Catholic Eucharist if appropriate circumstances permit them, and it is FOR such as these that the Canons make allowance to receive the Catholic Eucharist. I am 99.9999999% sure that a non-Catholic apostolic Christian who has a different attitude about the Catholic Faith will NEVER ask to approach the Catholic Eucharist, and so the Canon does not and cannot apply to them.
Perhaps you are also under the mistaken impression that the Catholic canons on non-Catholic apostolic Christians receiving Catholic Sacraments is some sort of CORPORATE admission for the Orthodox Church(es). It is not. Corporately speaking, the Orthodox Church(es) does not have and is not in communion with the Catholic Church(es), and the same is true from the Catholic perspective - corporately speaking, the Catholic Church(es) does not have and is not in communion with the Orthodox Church(es). The Catholic canon law only applies to INDIVIDUALS who will approach the Catholic Eucharist. It might interest you to know that there are many examples of INDIVIDUAL Catholics receiving in Orthodox Churches also. Just because it is not in their canon law does not mean it does not happen under the Orthodox principle of oikonomia.
Your point here is…well…pointless for two reasons:
(1) We don’t share the same dogmatic Faith with the Orthodox (at least as far as current understanding allows). So it’s a non-sequitur to bring up “Catholic unity” if the dogmatic Faith is not shared.
(2) The Eucharist is not just about the “communion of saints.” It is just as much about the VISIBLE communion of FAITH among laity and hierarchs. Your rationale sounds strangely like the invisible church theory of some Protestants.
Blessings,
Marduk