[Scotswife]

“If a new and legitimate Roman Catholic Church opened today, who would have to sanction it for it to be “official”?”

I’m just a layperson, so this is my best guess.

I’m guessing the local Bishop would have to approve of the plan, oversee it, and ensure it is properly consecrated upon completion.

If a consecrated Church within the Bishop’s jurisdiction is misused in this manner, it would make sense for the Bishop to excommunicate all those involved including the parish pastor that enabled the ceremony.

There are times when churches are reconsecrated when the sanctuary has been defiled.
I’m not sure when that is necessary and when it is not.

[Forest Keeper]

I’m guessing the local Bishop would have to approve of the plan, oversee it, and ensure it is properly consecrated upon completion.

Thanks, Scotswife. I wasn't sure if the Vatican (or a Cardinal, etc.) was directly involved with this sort of thing or not. I figured "somebody" had to sign off on it. :)