Well... "Mother Church" is your term and certainly applies to the religion of Lost Cause insanity, though naturally, being a born Democrat, you can't help projecting your own pathologies onto others, it's what Democrats do, by nature.
Be that as it may...
Your comment regarding Madison's letter to Trist is reasonable, or it would be if it didn't sound so much like jeffersondem calling Madison a "yapping dog" for his old age.
Funny how that works, isn't it?
Madison lived to age 85, about the same as my Dad, and I know he was perfectly capable of rational thought up until the end, especially on subjects he'd spent a lifetime studying & explaining.
So at 79 in 1830, there's no reason to think Madison was not expressing his decades long strong beliefs.
That's #one.
But #two is what convinced me, and that is the fact that nobody has ever produced quotes from Founders which flat-out contradict Madison's words, not even Jefferson's.
Indeed, any quote I've ever seen from actual Founders fits very nicely into Madison's framework of "necessity" (usurpations or abuses) or "mutual consent" versus "at pleasure".
Of course if you have quotes from Founders which do directly contradict Madison, I'd be interested in them.
But my guess is that for every one you might produce which directly contradicts Madison, I could find several consistent with him.