DC> So, no satisfactory answers from me, I'm afraid ... but re the
DC> A.t.thaka Vagga and its precise relation to the dhamma as we know it
DC> from the nikaaya-s, I just have one observation to make, and that is
DC> this: I think it would take an entire PhD dissertation to really go
DC> into this question and all its ramifications, and the end result
DC> would be a set of possibilities and probabilities rather than any
DC> convicing and definite conclusions.
If Sutta-Nipata is mentioned in Nikayas, then apparently it was
composed earlier. It is also quite homogenous, and suggests a certain
authorship. Then who may be the author of Sutta-Nipata. Some scholars
suggest that Ven. Sariputta is the author of Niddesa. I am not so sure
about Niddesa, but suppose that he, one of the first disciples of
Buddha, ordained before Ananda and Upali, was the author and carrier
of Sutta-Nipata. Even Rahula sutta (Snp 2-11) was said in the presence
of Sariputta.
Thus in the Pali Canon we may have several 'threads' of Buddha's
teaching as memorized by his various disciples.