And concerning the opinions of theologians, I have a book on the History of the Dominican Order up to the year 1500 by Hinnebusch,O.P. (vol. 2).  He has a whole chapter on the Immaculate Conception Controversy.  He says, "St. Thomas, along with St. Albert, St. Bonaventure, and all the other great scholastics, did not affirm the Immaculate Conception...Though not all members agreed in this interpretation, the Thomist school was convinced that its master held the opinion that Mary was conceived in original sin." (p. 172) 

"In 1455, the Master of the Sacred Palace, Aragonese Dominican James Gil, was so convinced that the immaculist doctrine was a grave danger to the faith that he urged Calixtus II, his fellow countryman, to define Mary's conception in original sin." (p. 177)

The history of the debate of the Immaculate Conception is quite interesting, as a side note. 

I've spoken with well over a dozen different priests on this topic over the years.  I've gotten well over a dozen different versions of what BoD is.  They are completely unable to agree amongst themselves what it is, what its effects are, who gets it, how you get it, whether it remits sin or not, whether it makes you a member of the Church or not, whether one needs explicit or implicit faith, whether it applies to just catechumens who get run over by busses on their way to baptism, or whether the ignorant savage on his proverbial desert island gets it, and on and on.

The bottom line is, they don't care what you believe about "it", just so long as you believe "it".  If this is a doctrine revealed by God, the very least they can do is tell me what the heck I'm supposed to believe regarding "it". 

Precisely.  This alone is prima facie evidence that "it" has never been defined.  Catholics do not assent to words or phrases, but to propositions.  If I believe in "BoD" what must I believe about it?  What PROPOSITIONS must I adhere to and assent to?  Propositions, for those untrained in scholastic philosophy are basically sentences, and no "There is such a thing as BoD" doesn't count.  You have to decompose what BoD means into sentences.  "You can be saved by desire alone."  So what is this desire?  "Well, it means perfect contrition basically."  Where does the Church teach this definition?  Answer: nowhere.  and so on and so forth.

Sadly, the greatest common denominator among ALL these flavors of and variations on "BoD" is ... that the Sacrament of Baptism isn't absolutely required for salvation.

Very telling, isn't it.  That a heretical proposition is what the greatest common denominator settles out as.

All BoDers care about really is they can find SOME way to make it that those outside the Catholic Church CAN be saved (despite dogmas to the contrary), including those who don't even have Baptism, and so that the actual reception of the Sacrament is not necessary for salvation.

That's really it.  That's their goal.  That's their begged question.  That's what they WANT to believe.  So they invent "BoD" to make it possible without having to deny a defined dogma.  Except of course they fail when they extend this BoD to non-Catholics, to heretics, to schismatics, to infidels.

They WANT to be able to deny EENS dogma without appearing to deny EENS dogma, where they can pay lip service that "oh, yes, of course, I believe that there's no salvation outside the Church", because they know to say otherwise would be heresy.  So they want to lip-service the dogma but then claim that you must accept it according to the CHURCH's "understanding" of it (aka their own understanding that they try to equate with that of the Church), which they go on to explain as you being a heretic if you affirmt he dogma exactly as it's written, and if you don't realize that the Church's "understanding" of "there is no salvation outside the Church" is actually that "there IS salvation outside the Church", and if you dont' understand the dogma as "meaning" the exact opposite of what it actually says, then YOU are the EENS-denying heretic.

This is every bit as absurd as Bill Clinton's ... "depends on what the meaning of 'is' is".  In this case, it depends on what the meaning of "no" and "not" is.  That's why the Church had to strengthen it repeatedly, with expressions like ABSOLUTELY no salvation outside the Church.  But nonthing has stopped them.