Is the Comforter a person? There are some sentences which are difficult to read in the Gospel of John, some of them lead me think that the Comforter will be a person, which has not come yet (A) whereas there are some which lead me to believe that the Comforter was the Holy Spririt (B).

(A)


  When he comes, he will prove the world to be in the wrong about sin and righteousness and judgment: about sin, because people do not believe in me; about righteousness, because I am going to the Father, where you can see me no longer; and about judgment, because the prince of this world now stands condemned. John 16:8-11


It seems to me that it has not happened already that those 3 fact were fulfilled, in particula the last one, I can't say Satan has been defeated again since Jesus death.


  13 But when he, the Spirit of truth, comes, he will guide you into all the truth. He will not speak on his own; he will speak only what he hears, and he will tell you what is yet to come. John 16:13


How can we say that a spirit hears? Additionally the greek word is ἀκούω, https://studybible.info/strongs/G191 shows the common usage on persons.

(B)


  And I will ask the Father, and he will give you another advocate to help you and be with you forever, the Spirit of truth. The world cannot accept him, because it neither sees him nor knows him. But you know him, for he lives with you and will be in you. John 14:16-17


This can only be the spirit because of the last sentence, and because otherwise how can he be forever?

So what are your thoughts?
The common interpretation for all Trinitarian Christian denominations are as follows:


John 16:8-11 : Jesus is referring to His still being in a human (bodily) form, but He will later send His Spirit (who is essentially the same as God the Father's Spirit) to "stand in" as Comforter for His disciples just in the way He was while in bodily form on earth before His Resurrection and Ascension.  But the dialog was set before crucifixion, so the 3 facts (sin, righteousness, judgment) were not yet clear.  At Resurrection Jesus 1) received glory because the Father raised him from the dead and 2) defeated death and Satan.  At Ascension Jesus 3) sat at the right hand of the Father.  And at Pentecost His Spirit came.

The Holy Spirit is the one who shows the world those 3 facts, testifying to what Jesus did to 1) convict the world of sin, 2) making righteousness available (because now Jesus is our High Priest in the heavenly temple interceding for us), and 3) pronouncing judgment to those allying themselves with Satan (Satan was defeated at Resurrection).   We are now in the era between Pentecost and Second coming where Satan is still allowed to rule the world, although his power is diminished, and the "underground resistance force" through the church is growing.

About judgment: In the "first coming" Jesus didn't come as a judge, but there is language in John about "pre-judgment" for those who didn't accept Jesus as the Son of God.  The "definitive" and "public" judgment will happen at the Second Coming when Jesus will come again, this time in glory, and all the world (saved and not saved alike) will see who are really the children of God and who are not.  See a more comprehensive explanation with Bible references here.
John 16:13: This Spirit is a person and therefore the language in John Gospel reflects this, as what the doctrine of the Trinity says.
John 14:16-17: You are correct in that the Spirit in this passage refers to the Holy Spirit who is eternal.  John's focus is to show how the world rejected the incarnate Word of God (Jesus) who came to the world created through Him but who didn't recognize Him (John 1:10-12).  The world didn't believe that Jesus was sent by the Father, and consequently the world didn't accept the Father either (despite the Pharisee's claims to know the Father better than Jesus, and who in fact executed Jesus thinking that they were doing the will of the Father).  That's what John meant by "neither sees him nor knows him", because the world did see Jesus physically, but not spiritually.  Only those who accepted Jesus as the Son of God will have the Holy Spirit living in their heart.