Sean, I'm a bit confused -- in your description of "the 3 types of SSPXers", you describe BOTH the 2nd and 3rd categories as "2nd and 3rd generation SSPXers". Are categories #2 and #3 really both from the same generations? Just wondering if there were any typos there.

I would add another group -- FIRST GENERATION SSPXers, mostly Baby Boomers, who have so much invested in the SSPX (time, youth, money over decades of putting money in the collection) they are suffering from the Sunk Cost fallacy -- they've invested so much, they're committed, even if the outlook today for the SSPX is objectively hopeless. Also, they're getting old and tired, and have no energy for "The Fight" (Tradition) -- according to Boomer culture, they have worked hard all their life, and by gum they DESERVE an easy, laid-back retirement for their Autumn years. "I worked hard to build up this church, and by gum, I'm gonna enjoy it!" They are frequently found saying things like, "I ain't goin' back to the catacombs! I paid my dues back in the 70's. We did the garage Masses, basement Masses, hotel Masses......."

The SSPX is not yet like the FSSP, at least in terms of doctrine, though they have contributed to this perception by the curiously friendly relations with bishops.  There has always been a very fine line when one admits those in authority have gravely erred while yet retaining their authority whereas the SV dispenses with this difficulty rather nicely, though not without creating their own major theological problems.  This is normally a purely practical question, similar to how one ought to interact with heretics, Jews, etc.  The "changes" of ABL are not really formal or substantial changes.  
Consider this: One day you are friendly with Michael and the next day you are angry with Michael.  Did you change or did Michael change?  Michael merely gave the occasion for treating him two different ways and you are merely responding to him under different aspects.  I suppose one could say Lad "changed" but the question is, why or in what manner?  What did Michael do to provoke you?  Nevertheless, are not both your dispositions directed towards the same formal end and controlled by the intellect and unity of purpose?  
I think those who jumped ship and started their own groups sense this difficulty so they try to make what is practical into something theoretical and substantially involving the faith.  Kind of like the SV who isn't satisfied with the notion that his opinion on the Pope is merely his opinion, no, he must raise it the the level of a theological conclusion!
But what of something like their so-called rebranding?  Isn't that purely practical?  No, I don't believe so.  I posit that to attempt to remake your "image" for suspect reasons while simultaneously insulting those who came before you is entirely another question.  Here, faulty thinking led to an action, whereas above, correct thinking led to two different dispositions.  

You are delusional.

If Bishop Fellay gives the nod to religious liberty in a CNS interview; if he accepts the hermeneutic of continuity as a means to accepting conciliar errors (as he did in the April 15, 2012 doctrinal declaration), these are significant doctrinal deviations.

Then at the practical level, if the SSPX starts accepting ministerial assistance from the ICK and diocesan clergy (as in the African District), this is a serious rebuke of Lefebvre’s position.

Rather than jumping ship too early, is this not a sign these people should have jumped ship years ago, before they could be conditioned into accepting ministrations from Lefebvre’s doctrinally compromised enemies?

In fact, why should the SSPX even exist today, if the faithful can just go to a diocesan indult or ICK Mass?