To be fair, "[near-]universal peaceful acceptance" of Francis as Pope probably addresses any questions about the regularity of the conclave that elected him, whether it violated norms set down by John Paul II, and so on.
But does UPA kick in when, possibly, another Pope is still reigning at the time of the election? Hard to say. These are uncharted waters.
"...respect must everywhere be shown for the feelings of all those who are attached to the Latin liturgical tradition, by a wide and generous application of the directives already issued some time ago by the Apostolic See for the use of the Roman Missal according to the typical edition of 1962." --- Pope St John Paul II, Ecclesia Dei, 1988