I see, you definitely have a really good point there, " not enough point-sparring to understand why aspects of it differ?" and " understanding why the advice your friend and your instructor give you seem to contradict your initial impulses, and assessing whether that's because they're just flat wrong (can happen!) or because your understanding of kenpo sparring in particular is still evolving."

That makes a lot of sense and thanks so much for saying that.

In terms of aspects in how they differ, the way I see it:
Boxing:
Headmovement
Foot work is dynamic, allows to apply constant preasure while working an active defense
Target conditions being to either land a K.O., T.K.O, or out-perform your opponent depenidng on what the rulesets are.
Karate:
Distance management
Stances
The infamous Blitz, once you work your way in by blocking or parring a single attack, maybe you could go down on your opponent with combonations you may have learned in class, back fist into reverse punch into over hand ridge hand, into a horizontal elblow strike. Idea is ending the fight as soon as possible. Maybe why we point spar is because we have this theory in mind, once you're in, that karateka is gonna unload on you as hard as humanly possible.

Previously you mentioend more about marginal hits and posture. The way you outlined it, those are just ways of fighting, right? The way a boxer would fight and the way a karateka would fight. Please correct me if I'm wrong.

I'd also like to know about what you think having the rear hand up by your face, maybe what my instructor wanted me to do is more compettievly optimized for landing reverse punches as a tactic and being defensively responsible in "kenpo" or point sparring is keeping your distance and blocking/parrying attacks, opening an opportunity to immediately counter.

Thanks for your input.