I have not seen anything that suggest a religious test for residence, and I suspect that would be illegal under various civil rights statutes.
As you know there is nothing in Catholic moral theology that disagrees with the Orthodox Church, although the Catholics tend to adopt a more legalistic approach than, perhaps, the Orthodox.
I think its more about the laws than the legalisticness, but even in doctrinal thelogy there's not much (something, and something tangible but not much) which separate Catholic and Orthodox.
Looking at the website, they make it clear that any race, religion, or ethnicity is welcome. I think anyone willing to live under the community rules would have no problem buying a house there. It will be interesting to see the makeup of the community once it is completed and again after a decade or so. I think initially at least it will be majority Catholic, based on the university.