(1) The only repository of tradition is the Magisterium.
The SSPX proves here that it is deluded into believing that it possesses the Magisterium.
(2) There is nothing the Holy See "must" do for the SSPX - this is not the language of those who pursue the obedience of faith.
(3) Is Pfluger now the head of the SSPX and able to make authoritative statements on their behalf?
Where is Fellay?
At this point, I say good riddance to these Latinate Protestants.
You prefer the modern mass? If not, you should be thankful that God inspired the SSPX to successfully defend the Latin Mass and Catholic Tradition from modernist quislings who overran most other parts of the Church in the West.
Good question. I have a feeling that regardless, there will be a real schism (the more proper term, instead of "Protestant," which carries a specific connotation. They will be more like the "Old" Catholics or the Orthodox). It is just a matter of how big it will be, even with the overtures that the Pope gave with his removal of the excommunications. I don't think this priest is doing any good for this process. Silence would have been better, which is, interestingly enough, Bishop Fellay's M.O. during most of this process.
In more felicitous news, I hope the matter with the traditionalist religious who follow the Redemptorist rule in Scotland (and who ended their affiliation with the SSPX after the motu proprio) is finally resolved.