In my opinion, option 1 is the way to go for the official library. Obviously, coming up with a way to automate the creation of that file would be a very good thing.
Unfortunately, it seems like for CC purposes, the Parts Tracker page for each texture would also need to have CC attribution (with all authors listed). For example, this page lets anyone download the PNG file, but does not mention licensing of the file anywhere:
https://www.ldraw.org/cgi-bin/ptdetail.c...03441a.png
That was (presumably) never a concern with DAT files because the licensing info was present inside the files in plain text.
Unfortunately, it seems like for CC purposes, the Parts Tracker page for each texture would also need to have CC attribution (with all authors listed). For example, this page lets anyone download the PNG file, but does not mention licensing of the file anywhere:
https://www.ldraw.org/cgi-bin/ptdetail.c...03441a.png
That was (presumably) never a concern with DAT files because the licensing info was present inside the files in plain text.