I am not sure I would classify DS hacking as obscure but hey.
I did briefly look into Dororon! Yokai Daikessen!! when I was looking at the various sound formats the DS games have used (the vast, vast majority use the SDAT format Nintendo made so deviations are worth noting) and this was a different/custom one combined with the standard SDAT. That said the formats you mention are no longer used in that game (or at least no extensions and there are no magic stamps with them).
Still I had a look at the older games.
The NTF stuff seems to be much like other NTF stuff I have seen and is graphics -- you will need a tile editor capable of displaying custom tile sizes (crystaltile2 and http://code.google.com/p/tiledggd/
being among the few that do well here). It looks marginally complex and the palettes do seem to be included in the files.
Reading the threads you linked and looking in general the SWG stuff appears to be one of those combination text and scripting formats that I am increasingly seeing more and more of on the DS. I shall have to look further if I have the time.