The Autobiographical Tolkien - 'Leaf by Niggle'...

[HerenIstarion]

Sharon maybe I was wrong myself, sorry

Niggle’s art is not so vain in the story itself:

"I think he was a silly little man," said Councillor Tompkins. "Worthless, in fact; no use to Society at all."
"Oh, I don't know," said Atkins, who was nobody of importance, just a schoolmaster. "I am not so sure: it depends on what you mean by use."

It’s “nobody of importance” that's saying that, yet “the last will become first”

When SOWM came out, JRRT already was "published" author, so Smith being himself, and Alf representing the gift (or the giver) he had in writing, Nokes may be pictured as unlearned critic(s). In Niggle he was not certain of anything yet. Parish's wife does not make the Edith theory incredible - Parish and his wife together may represent Edith, Parish being part of her personality most close to JRRT. Remember Parish's refusal to go with Niggle and shepherd based on an argument that his wife was to be sent after him. But those are all speculations, of course.

One can also speculate that JRRT is represented by both Parish and Niggle – one being his “lower” part, and other “higher” (some kind of jekyll and Hide). in afterlife his lame “lower” part of mentality is set right, and the both work together creating things impossible otherwise. In this case Parish’s wife becomes edith, and when she grumbles “this Niggle” she is grumbling against JRRT’s “higher” half, one interested in poems and not in bills.

Well, enough with speculations for now