Earlier, I said:

The fact that brains increased by a factor of 2 to 3 orders of magnitude in 3 divergent branches of placentilia is evidence to me for robustness in selection for high intelligence.

Which is in error - I should have said "evidence indicating high intelligence is a robust developmental attractor". As you point out, evolution rarely selects for high intelligence in individual lineages.

.. is hardly strong evidence that near-ape-or-better intelligence is a highly probable feature of life-in-general.

No, but this has become a digression. For the potential big picture galaxy models in consideration, we are more concerned with discerning between intelligence being highly improbable or only weakly improbable. The impact arising from the difference between weakly improbable and highly probable is relatively minuscule in comparison.

I am claiming only that the evidence for parallel development of intelligence on earth is sufficient to conclude that intelligence is in the vicinity of weakly improbable to probable, rather than highly improbable.