ATM, WotC has not licensed any character generator, TMK, to produce datasets. Until that happens, you'll have to enter the information on your own.
You can create your own datasets.
I'm pretty sure that Wormtail is the one that killed Cedric in the book.
I saw the movie last night with my sister-in-law (my wife and her boyfriend have no interest in the series). We both enjoyed it, but I could definitely tell that there were pieces missing from the book. However, I think...
We know its OGC, but the code monkeys have said it would take quite some time to get gestalt to work properly. You could, as a stop-gap, create datafiles for the specific classes. I realize that's a pain, but it is an option.
I've always typed out my personal stuff, so don't use the lst editors. However, after entering your info, have you a) restarted PCGen and b) loaded the Homebrew source?
Found the file I have...but it somehow got corrupted. Anyway, the title is Class Construction System by Greg "Magecraft" Korynta.
Then there's ST Cooley's Buy the Numbers, but that isn't building classes per se, just abilities.
PCGen has templates in it that you can apply to various creatures. So, in your example, you could pick a lion, and then apply the fiendish template to it.