I was surprised to see that LAME decided a 32kHz sampling rate was all I needed. But with a max frequency of 15kHz, that's hard to argue with.
Looks like you're pretty far into the project, otherwise I might have suggested you try V5, V6 and V7 and ABX them to see if you can hear a meaningful difference.
You should archive the originals in one of the many lossless codecs. This way you can set up the tags the way you like, and those tags will carry over to the lossy files when you reencode.
1) Yes2) and 3) Well, you seem already to be quite sure that metadata would not be of much use, so perhaps we can discount that from the discussion of whether lossless compression overall is worthy of consideration.5) Lossless compression may be especially effective at compressing audio that has relatively little high-frequency content, relatively high dynamic compression (a common concomitant of FM-based broadcasting, if I recall correctly), and possibly other traits that your sources might possess. Have you tried compressing any of your files to see? I could counter your citation of ever-expanding capacities with the equally real trend of ever-increasing processing speeds and ever-faster codecs. So, compression may still offer something to you.
I guess I'm hesitating because the FLAC conversion would add one more step to the workflow
I feel like I should take all the FLAC discussion to the FLAC forum.Maybe I should upload some mp3s of said radio show with the LAME settings I've chosen and see if others think the 32kHz sample rate at V6 sounds good.
It's a shame fb2k didn't adopt any of the wav metadata schemes that are out there