I doubt that the married bishops will be grandfathered in.
Just relating to the Orthodox where a priest may be married, but in being married he more or less forfeits the bishopric office.
The proper response from the TAC bishops is that they would rather be priests in a Christian church than bishops in a pseudo-Christian one. The proper response to that from Rome would be to name the TAC Primate as a cardinal, and dispense him from the requirement of being ordained a bishop, as they did for Cardinal Dulles.