The entry for "Soon May the Wellerman Come" tells us Page 10, words and music (coded "PD") "Public Domain with informant (not necessarily the composer) Frank Woods" and "Earliest published source this collection."

That's great, Walt, thanks!

Your information about the content of the 1972 anthology, then, tells us that the source for "Wellerman" was only given as F. R. Woods (from what you shared with me), without a date. The information about his first name (Frank), the year of meeting (1966 or 1969), and the the tidbit about learning from his uncle seems to have come from elsewhere. Again, I suppose it is oral information shared with some people in the NZ folk revival scene. Because although Dr. Brown, who interviewed Colquhoun, gives us the first name/Frank and the place of meeting (Wairoa), he doesn't give share the uncle part or the date (1966, quite possibly erroneous) as the folksongs.org.nz site does.

Steve,

That makes sense to me. (Though I'm not the one to do it!) The "blow my bully boys blow" part is reminiscent to me of the aroma of newly-composed nautical songs that mix genres, borrowing this CHANTY trope and sticking it into a ballad.

Additionally, I thought the "tonguing" and "billy of tea" parts are suspicious, and here's a wild hypothesis:

There doesn't (yet, to my eyes) appear to be a robust documented usage of this "tonguing" thing. Where else do we see it? Well, in the song that Colquhoun's circle presented numerous times: "Come All Tonguers." That song originally came to them from a batch of whaling songs shared by a guy from the U.S., Leebrick, who in turn had got the batch of songs from the daughter of a whalerman operating near NZ. "Come All You Tonguers" and others in the batch appear to have formed the core of the most ~authentic~ folk songs that Colquhoun's cohort worked with. The song was a key item. My thought is that if C or a friend were to want to pen a new ballad about whaling out of NZ, then they would feel they definitely needed to work in "tonguers."

"Come All You Tonguers" also includes the line, "I am paid in soap and sugar and rum."

I am stabbing out blindly here because I have not done the work to determine whether "tonguing" was a prevalent thing or, as my casual experience suggests, was more rare. On one of my YT videos, Australian chanty-singer Don Brian writes,
"Having looked at many whaling logbooks from this area and searched New Zealand and Australian newspapers, I can find no reference to tonguing as Whaling related activity, although timber workers (also supplied by the Wellerman Ships) use this term in preparing planks..."
Being skeptical of the prevalence of "tonguers" (let alone "tonguing") I feel as though there's a confirmation bias loop: Someone finds "Wellerman" and asks "What's tonguing?" Someone else says, "Tonguing was XYZ because, for example, see this song 'Come All You Tonguers'." Together, the two songs of supposed historical origin make it look as though "tonguing" was this big thing-- so big, in fact that "several NZ whaling songs sing about it"! Tonguing is "confirmed"!

Unless someone can enlighten us to the contrary, that tonguing was a big deal, then I'm inclined to think a modern song -- "Wellerman" -- cribbed from ideas in "Come All You Tonguers."

The hypothetical writer of such a song may also have observed the multiple appearances of "Billy" (billy-can) in a small body of folk songs ascribed to NZ, and thought it would give the nationalistic "NZ flavor" to include "Billy of Tea" in "Wellerman."

I'm not making a strong argument here to prove that someone in the NZ folk revival composed "Wellerman" from whole cloth. I'm just raising the possibility. Given the (apparent) lack of documentation (and resultant ambiguity) on who "Frank R. Woods" was, there is little more than faith and wishful thinking to recommend the idea that Frank Woods was passing on a traditional song. Can't disprove it, but there are good reasons not to believe it.