I can see that the first alternative is not possible.
If I may dig into the second alternative further as there are inconsistencies I’d like to understand. Strong arguments for vitakka vicara as jhana factors are that we have four accusatives in a row:
savitakkaṃ savicāraṃ vivekajaṃ pītisukhaṃ
But only two of them are qualified by the prefix sa-. We don’t have a sapitisukham
In the standard formula continuing the first jhana (he floods his body etc.) the other factors are mentioned twice, vitakka vicara not at all:
So imam-eva kāyaṁ vivekajena pītisukhena abhisandeti -and again
sabbāvato kāyassa vivekajena pītisukhena apphuṭaṁ hoti
So there is something different about vitakka vicára, they are not equal jhana qualities. And probably the sa- that they have gives us a hint about it.
Again another possibility would be that the sa- comes not from saha (with) but from santa (good), as described in Duroiselle §555. The text would then be “good thought, good movement, seperation-born, joy-gladness”. But I don’t see much use in that reading.
My current understanding so far is this: The Jhana proper is vivekajaṃ pītisukhaṃ jhānaṃ
vivekaja - how it came about
pitisukha - its quality
vitakka vicara - factual aspect (sa-), but not a “quality”. Where piti sustains the second, I don’t think we can say that vitakka “sustains” the first in a similar way.
Does it make sense or do I misunderstand the text still?