Well see.... if you guys are able to Extract the contents of said CPK and you get tons of files without a TOC, how are you going to re-build said CPK?
Has anyone tried editing the CPK, then rebuilding it? Without a TOC I'd imagine it'd be a lil difficult.
EDIT: Also as far as "Redubbing" goes, don't bother. Re-encoding PMF files is very difficult and getting the near raw audio from the episodes (No Background Music or Effects) would be incredibly difficult. Also there's a good chance that there are new scenes in the game that aren't in the shows or movies.
Just translate the sub titles on the videos, if you can find them.
To be honest so far I've been testing a redub in latinoamerican spanish (the version I grew up). I've only redubed the first cutscene, where they are standing there then the digivices appear and the waterfall takes them to the digiworld. The scenes are shorter than the anime, and the result wasn't perfect but it was pretty good.
There are no new scenes in the game that aren't in the show.
You can watch this if you want, it contains spoilers... but if you already watched the anime, then it won't spoil you anything

:
Of course that there is no original audio from the part of the game where all the digimon trainers find themselves in that kind of "Matrix" world (I dunno what it is, I haven't played the game yet, just know that it exists), and also, I don't know if there are secondary missions which are things that never appeared on the anime before. But for the main story, it's all there.
However I agree with the first thing you said; re-enconding pmf files IS very difficult. A lot of steps. I'm not done yet; I have to convert the AVI I extracted into another kind of avi, so that it can go into the UMD Converter along with the wav file, in order to obtain a .pms file, which I should then convert into pmf. Then repack it into the CPK, and then put the CPK in the ISO and see if it plays on the PSP. I don't have the time today to do that, but I'll test it out some other day.
If someone knows any kind of way to do this but more easily and directly please tell me. Also, if you know about someone who has redubed PSP games in the past, tell me who so I can contact him for advices.