You bring up
John 16:8 in the Reformed context, which tries to narrow its meaning, by using "world" to not refer to the entire human race, which is what Jesus means.
I think that he brings it up as he understands it ( which you refer to as "the Reformed context" ), which is your right, IMO.
His right, which I understand in the context of the rules of this site, is to conduct himself so as not to break those rules while also bringing up his beliefs about what he sees the Bible teaching.
Personally, I can see it being understood as meaning the "non-elect" because of what the entire passage states.
The Holy Spirit reproves
the world of sin, and the passage goes on to say that that reproof is done because they ( the world ) does not believe.
"Nevertheless I tell you the truth; It is expedient for you that I go away: for if I go not away, the Comforter will not come unto you; but if I depart, I will send him unto you.
8 And when he is come, he will reprove the world of sin, and of righteousness, and of judgment:
9 of sin, because they believe not on me;
10 of righteousness, because I go to my Father, and ye see me no more;
11 of judgment, because the prince of this world is judged." ( John 16:7-11 ).
In the above I see that "the world" here is all men
outside of Christ, and not "the world" of the "whosoever believeth" as I see John 3:15-16 and 2 Corinthians 5:19 saying.
I also see that "reprove" ( how the AV translates it ) and "convict" ( how some others translate it ) mean:
Reprove:
"reprimand or censure (someone).
"
he was reproved for obscenity"
Convict:
" declare (someone) to be guilty of a criminal offense by the verdict of a jury or the decision of a judge in a court of law."
and not:
" to convince, ( supernaturally and spiritually ) of error or sinfulness".