Ok, I uploaded a new archive with all the files converted to .aiff or .wav, that Renoise can use easily.
Some original files where raw PCM with no header, some others where IFF files with a header documenting the sample rate.
The .aiff files are the raw PCM originals plus a generated header that Renoise can read, so most of these samples are now tuned in C out of the box for modern DAWs.
The .wav files are the IFF originals converted by SoX (Sound eXchange), and are as tuned as the original sample was. Except that now Renoise can read and use the sample rate from the .wav file (it could not use the IFF header in my experience).
There is an extensive README.md in the archive, to help documenting and reviewing the conversion process, and what I have learned on the way.
Cheers!