@The Milanese Catholic states (Or whatever you're calling it)
What exactly are you guys schisming from? As for joining Oriental Catholicism or Milanese Catholicsm, that's up to you. Its true that hanging out in China we can't physically do much to help you right now.
That said, I think if you want to start with anything resembling RL Catholicism you'll probably have to schism off of us, or outright declare heresy from the Celto-Catholics or Cathars. It might be easier to schism off of us.
Whatever you guys do, the Empire of the Dragon is willing to work with you. Your religion is much closer to ours than any other religion in the world, including the Celto-Catholics. You would be, however, throwing out the baby with the bathwater as it pertains to Celto-Catholic revelations.
We highly doubt any of your Catholics will exist in our lands, but if they do for some reason, we will respect their rights to worship, in return for the protection of any Oriental Catholics in your region.
And whhile, of course, we don't consider your pope to actually be the pope, we are more than willing to openly discuss religious policy. Our theological disagreements are fairly minor, and you seem to have one very notable saint outside your canon