The various peds have a metadata file that OpenIV can't open.  I assume that contains information like linking various versions of the peds with their correct voices.  If I want to alter which voice a particular version of a ped uses, is there a way to do that, or is that beyond current capability?

Mostly. The issue with those files is that they're all hashes, even after decryption, and what's been figured out was trial and error, and not really publically released.  The metatoolkit won't be updated anymore, too, unless someone else takes over it.

5 hours ago, Asahammer said:

The various peds have a metadata file that OpenIV can't open.  I assume that contains information like linking various versions of the peds with their correct voices.  If I want to alter which voice a particular version of a ped uses, is there a way to do that, or is that beyond current capability?

Some user friendly tools to edit those are being worked on by some talented people (not me).