Preliminary thoughts, subject to future amendment:
1) I have no principled objection to a rapprochement between the SAJM and Fr. Hewko, as most (but not all) of what divides the two camps are differing pastoral approaches to the apostolate, rather than contradictory doctrinal positions. Those are matters of prudence about which one ought not be dogmatic, and respect (perhaps while still disagreeing) that others may have good and reasonable grounds for reaching different conclusions.
2) It is certainly true that +Williamson often says things which one could easily foresee would cause disagreement and controversy among trads, and that minimally, would have been better left unsaid (eg., Valtorta, Thuc, various other apparitions, etc.). Consequently, His Lordship must sleep in the bed he makes, for having chosen to frequently kick these hornets nests. On the other hand, is it really necessary to excommunicate him?
3) Is it possible for Williamson and Hewko to agree to disagree and collaborate, or must a rapprochement between the SAJM and Hewko presuppose a drifting apart between Williamson and the SAJM? For myself, I think the former is possible (eg., Lefebvre cautioned his seminarians against Valtorta, but didn’t part ways with Fr. Barielle, who advocated it).
4) Who will staff Fr. Hewko’s seminary? Will the SAJM and/or Avrille send at least 4-5 more competent priests to teach, or will +Faure be content to ordain seminarians formed in a 1-man program with occasional visiting priests. One would hope there would be a continuous and rigorous oversight in this most important endeavor. An absentee seminary formation is absolutely unthinkable, but I doubt Fr. Hewko is prepared to abandon all his missions. He needs help, or the project is impractical. St. Thomas Aquinas himself couldn’t cover all the doctrinal bases for an adequate formation, and only the very reckless would justify acceptable incompetence because of the crisis.
5) Fr. Hewko would restore the 1951 missal. That is surely a great move, but what would the SAJM say about that? I wish the SAJM would also adopt it, but that’s not likely. Perhaps Hewko’s seminary would retain it as its own charism.
Anyway, these are my initial thoughts, and it seems that as most of the issues are practical, rather than doctrinal impediments, if both sides want it bad enough, perhaps it will happen.