I agree with you that one's Enneagram influences the outward appearance of one's instinctive stackings; the more so when the "leaning" of the instinctive stacking runs counter to the, err, the "stereotypical" bent of one's Enneagram: as for example an SO-dominant E9 INFP, or an SX-dominant E4 INFP.
I would suggest that the SX, while it can manifest in sexuality, often ends up manifesting as raw naked INTENSITY, and seeking fusion with another confidante or lover, the whole "soulmate" or "mindmate" thingy.
The SO, I would say, is not just "being social" or climbing the social ladder, but what Isaac Asimov attributed to the Kloros in the short story C-Chute
of social groupings, of cliques, of political or friendship alliances. (Incidentally the last line of that story *really* ties into the SO instinct, though if you squint just right, you could make it apply to any instinctive stacking.)
For SP, I have a hard time matching it to anything but "prudence" and all that: of which the typical life-style manifestations *would* be food, money, safety - though, I'll gladly add to my fount of knowledge should anyone wish to correct me.
Thus spake the 5w4 SX/SP...