Suppose it were granted that the suttas in question were from approximately the same time as the rest. The Atthakavagga and many suttas consistent with its no views message still are at odds with the rest of the canon doctrinally.
When the Buddha says
The cleansed one has no formulated view
at all in the world about the different realms.
Snp 4.3
and confirms
And what have I not declared? I have not declared the following: … ‘a Realized One doesn’t exist after death,’ ‘a Realized One both exists and doesn’t exist after death,’ ‘a Realized One neither exists nor doesn’t exist after death.’
MN63
But then turns around as says
Feeling the end of the body approaching, they understand: ‘I feel the end of the body approaching.’ Feeling the end of life approaching, they understand: ‘I feel the end of life approaching.’ They understand: ‘When my body breaks up and my life has come to an end, everything that’s felt, since I no longer take pleasure in it, will become cool right here. Only bodily remains will be left.’
SN12.51
It is difficult and arguably impossible for an honest person not to see a glaring contradiction here. In SN12.51 he is declaring what happens to the Buddha after death.
Karmic retribution falls prey to similar arguments.
I doubt anyone would care if the Atthakavagga was very early Buddhism or not except that it so blatantly contradicts so much of what modern Buddhism holds dear. Something has got to give.