I think that one sees where a Sarah and Burke appear to cautiously favor the Tridentine Mass over the NOM, so those two might be the only ones who still have Catholic faith left ... but then they've both lavished praise on the heresiarch Wojtyla.
And Burke has said the SSPX is schismatic.
Thus, whoever they elect must convert to the Catholic Faith and express this externally, such as by declaring Vatican II utterly null and void.
The Modernist electors are still able to perform a valid election:
Apologia de comparata auctoritate Papæ et Concilii, n° 744:
impossibile est Ecclesiam relinqui absque Papa et potestate electiva Papæ
[It's impossible that the Church be left without a Pope and the power to elect a Pope.]