You have no idea how much scrutiny that the current views have undergone. It is a very very safe bet that you will not begin to be able to find anything that comes close. After you get your PhD in the field you might know enough to make a small change somewhere.
I have no idea who you quoted here, but it certainly wasn't me.
Although your comments are interesting, I personally don’t put much stock in marsupial migration relative to the topic at hand here — physical laws and supposed reversing geomagnetic polarity. Incidentally, even if the fossil record were complete and correctly interpreted, we should ask whether there are alternative explanations for the migration patterns to have occurred. I believe there are, but you will need to investigate that for yourself.
Questions of biogeography don't have any obvious application (to my mind) on the issue of magnetic field reversal. If you'll refer back to the post to which I was replying, I was confirming Jazz's memory of marsupial phylogeny and biogeography. The latter DOES have relevance as an additional line of evidence that continental landmasses which are now halfway around the world from each other were once joined, which was the point. If they weren't, then there's no other explanation for the distribution of these organisms.
The "weird" comment was in relation to N. America being the original home of most marsupials. They then disappeared completely from the continent, then were re-established by immigration from continents to which they had originally dispersed. I just think it's interesting (hence, "weird") that they had to recolonize their "birthplace" as it were.
As far as this bit goes:
Do we know these things by inferred association from analysis of marsupial migration... drawing conclusions from an incomplete and ever changing fossil record?
We "know" this because we have a record of primitive marsupials at point A, then they disappear and other marsupials appear at point B and C, then different ones later at point D, and finally much later even more derived marsupials reappear at point A again - with these latter related fairly closely to intermediates found at point B. Infer what you will, this is the observed evidence from the rocks.