From the link in my previous post:
“To belong to the Personal Ordinariate, a person or family must be eligible. A person is eligible for membership if they, their spouse, or any member of their family is or ever has been Anglican, Episcopalian, Methodist, or AME [African Methodist Episcopal Church]. This applies even if the person or their spouse has already become a Roman Catholic. Catholics who are reconciled to the Church and those Catholics who will be completing their sacraments of initiation in an Ordinariate community are also eligible for membership.”
As far as which denominations a congregation can come from (an entire congregation looking to become Catholic via the Ordinariate), the four listed are the only ones I’ve ever read were admissible. HOWEVER, as it also says, ANY person who is seeking full communion in the Church (i.e. anyone who wants to become Catholic) can do so via the Ordinariate. So, for a couple of examples:
A person was brought up Catholic, but did not receive Confirmation could become a member of the Ordinariate by receiving that Sacrament in an Ordinariate parish/group. Or, any person - regardless of their past religious affiliation (or lack thereof) - can become Catholic in the Ordinariate.
And one last thing, just to note, if a person is already Catholic (received the Sacraments of Initiation) and did not come from one of the four listed denominations before they became Catholic, they can of course still attend Mass at an Ordinariate parish/group. There is also a provision for such a person to register as an “Affiliate”, which, as the website says: “While this will not make you a formal member, it will allow us to remain in touch with you, send you updates, and generally keep in touch.”
If there were an Ordinariate community anywhere close to me I would be there in a heartbeat…but there isn’t (I’ve spoken with an Episcopalian co-worker, trying to see if there was any talk of “making the swim”, but it doesn’t sound like there is at present ). If I wasn’t discerning a vocation as a monk I would be seriously considering moving close to an Ordinariate community