Hey,
In SN12.64 the order of the factors may be non-standard, which is a tiny bit unusual, but nothing to analyze too deeply, imo. They should just be read as happening alongside one another. Notice that it uses the word ‘where’ (yattha). I.e. where consciousness is reborn, there a body and immaterial aspects (namarupa) are formed (conceived), that is where karma (sankhara) comes to fruition, and that is where there is rebirth. It doesn’t mean to say, as far as I understand, that they succeed one another in time.
Because otherwise the cessation sequence, where the factors are also out of place, would also span three lifetimes, and that would of course be silly! This cessation happens at the end of the life of an arahant.
I think ‘conceived’ is a good translation, much more explanatory than the overly literal “descent”. Thanks for the dictionary references! I didn’t know the Concice dictionary suggested it. I was already using it myself before Sujato opted to use it too.
Another good reference is AN3.61.
Supported by the six elements, an embryo is conceived. When it is conceived, there are name and form. Name and form are conditions for the six sense fields.
I wrote something related to this before: