i can provide these quick notes, at least:
-the earliest mention of When Funnies Were Funny ive found in available industry books online is in the 1976 International Television Almanac (i do not have access to the 1975 edition), which mentions there are "42 cartoons" available. every subsequent entry still mentions there are 42 cartoons, even with the sales sheet omitting the two "Mickeys" (perhaps they were still available internationally? could explain why they showed up in europe throughout the 80s.)
-36 of the 42 cartoons are listed in the July-December 1975 edition of Catalog of Copyright Entries
astute eyes will notice the when funnies were funny cartoons all have copyright dates of either 1971 or 1973 (excepting Oceans of Trouble, which has a date of 1974, and two shorts with a '1963' typo). stock music tracks date to 1975 at latest ive found (though i won't rule out the possibility of these tracks being published earlier). i have not yet found mentions of the package from before 1975 in publication, however.
even if there are potentially more in existence, i can at least say this list covers all the cartoons confirmed to have been released and exist.