Hi George -- I just joined Mudcatters a few hours ago myself, so I don't know Frank, and I don't know whatever info he's given about you (yet). I'm just reading discussion postings, haven't had a chance to look at the database yet. One of the first things I came across in these discussions was your posting of the Pawnbroker's Wife. Love it! (I can almost hear a tune in my head, but where can I find "The Waterford Boys"?)
What specifically do you want to know about the copyright situation? Can't guarantee that I'll have answers, but try me.
Truly trad. songs aren't copyrighted, except maybe someone's particular arrangement (printed or recorded) of same. Newly written songs may or may not be, depending on whether the authors/composers bothered to copyright them. If someone has put a "c" inside a little circle, that indicates copyrighted (or a "p" for performance rights), and technically one is s'posed to pay royalties to use copyrighted materials (at least for public performance, or at least public performance for monetary gain, recording, etc.), not photocopy them without permission from author or publisher, etc., etc. Seems to be an intersection (or clash) of ethics and capitalism.
(Somebody please correct me if I've given misinformation here.)
I first heard "Lavender's Blue" as an English nursery song when I was a nursery kid myself, ca. 1940 (possibly with political overtones or undercurrents, I learned later in some college folklore course?), and also heard someone like Ella Fitzgerald (or thereabouts) sing it in a croony-pop rendition (probably mid or late 1950s?). I'd forgotten all about it until a friend suggested, a couple months ago, that we include it in some repertoire we were putting together for a potential gig. Shortly thereafter it surfaced again in an SATB arrangement (maybe from the King's Singers) that a small chamber-singers group I'm in was considering for our upcoming performance cycle -- so it must be serendipitously making the rounds these days. It's included in the Sing-Out collection "Rise Up Singing" (p. 29), which says it's English trad., first printed in 1680 as "Diddle, Diddle." If you find out anything else about its history or variant versions, I'd like to know too -- thanks.