I like "Resisters" or "Resistance." That's what the SSPX was supposed to have been all these years anyway: Resistance to modernism and the Revolution in general. So the current "resisters" are simply carrying that on, resisting the Revolution wherever it turns up, even within the SSPX.
I also use "Accordistas." It did seem imperfect in that it might sound like it implies only pro-premature deal with NewRome, i.e. emphasis on the "deal", when the crisis is about more than that. It's also about the softening of the SSPX, the creeping changes etc... But maybe "accordista" still covers that too, because the softening is largely for the purpose of coming to an agreement (accord) with NewRome anyway. In any case, "accordista" works well enough, and those familiar with this crisis get what is meant, so it works for me.