Ascertaining that a priest had been ordained SSPX is usually fairly straightforward. You can just Google their name "Father [so-and-so] ordained [or ordination] SSPX" and then maybe add "Winona" or "Virginia" or "St. Thomas Aquinas Seminary" etc. If they were ordained there, you can usually find some announcement of their ordination. At that point, doesn't matter which of the current SSPX bishops ordained them.
NOW, a Huonder doing ordinations ... that would be a whole new can of worms, and it may be why God took him from this earth.
That's also why I fear about the next bishop they'd get approval for, where they'd try to get one who was Conciliar-ordained, or Conciliar-bishop-ordained (e.g. Huonder). I do think that's what Huonder was there for. They started boiling the frog by having Huonder do some holy oils, sending out that trial balloon to assess reaction. They were going to do it again, but Huonder dropped before he could.
Huonder was already saying Mass publicly at the seminary, so the priests were forced to become accustomed to it ... or else leave.
Next step likely would have been for Huonder to "ordain" some priests. Then, of course, after a few years, one of those "priests" would be chosen to be the nexft "bishop". I believe 100% that this was their plan, but God intervened to spare the faithful.