I've been thinking about this one for a couple of days - I hope you weren't about to post a new one in the hope of more takers!
A thought about the first Sutta:
"Now, what, friend Sāriputta, is the pleasant, and what is the painful?"
"Rebirth, friend, is painful; non-rebirth is pleasant. When, friend, there is rebirth, this pain is to be expected: cold and heat, hunger and thirst, excrement and urine, contact with fire, contact with punishment, contact with weapons, and anger caused by meeting and associating with relatives and friends. When, friend, there is rebirth, this pain is to be expected.
The use of the definite article certainly seems to imply that Sariputta is being asked for a definitive or comprehensive answer, as opposed to mere instantiations. The question "What is pleasant?" could be dealt with via a couple of illustrations, but this requires more. So Sariputta's answer seems, in the absence of any correction of Samandakani's assumptions, to equate rebirth with pain. All the more so, given that "non-rebirth is pleasant".
The "expected" pains which follow are therefore interesting as regards their status. Are they
the same as rebirth - forms or instances of rebirth, which has in itself no pain over and above these physical and psychological sufferings? Or are they
other, albeit lesser, pains, which happen as a result of something being reborn? This obviously brings us back to the "great rebirth debate".
"When, friend, there is no rebirth, this pleasantness is to be expected: neither cold nor heat, neither hunger nor thirst, neither excrement nor urine, neither contact with fire, nor contact with punishment, nor contact with weapons, and no anger caused by meeting and associating with relatives and friends. When, friend, there is no rebirth, this pleasantness is to be expected."
So the specific pains of contact are not to be expected, but pleasantness is to be expected. Does this mean that
1) Something is reborn which can experience the expected pleasantness? This would mean interpreting "no rebirth" as meaning that there is no rebirth of the
painful states, rather than there being no rebirth of anything, period.
2) Some things are reborn, but they are experiences - pleasant ones - rather than an experiencer.
3) Nothing whatsoever is reborn, and this is in itself a pleasant experience (which I confess I can make no sense of at the moment - but maybe I need more tea!)
4) Nothing whatsoever is reborn, and the mere expectation of this is pleasant before the fact, so to speak, as opposed to being pleasant when it happens.
In the second Sutta, this bit is interesting:
"Not delighting, friend, in this Teaching and Discipline is painful, delighting in it is pleasant. When, friend, there is no delighting (in this Teaching and Discipline), this pain is to be expected: whether going, standing, sitting, or lying down, the pleasant and the easeful are not attained; whether one has gone to a village, a forest, the root of a tree, an empty hut, an open space, or in the midst of monks, the pleasant and the easeful are not attained. When, friend, there is no delighting (in this Teaching and Discipline), this pain is to be expected.
Here, the implication is that the only way to attain "the pleasant and the easeful" is by delighting in the Teaching and Discipline. Which seems to conflict with everyday experience of unwholesome pleasures, unless of course the terms "pleasant and easeful" are being used in a different way.
You can certainly pick 'em, Mike!