The Paraclete / advocate / comforter is a person and Holy spirit / Holy Ghost is not a person etc... I will limit my response as much as I can – it would be very long to respond comprehensively to every detailed point that is raised. (My Brackets)
John 14:16 "And I will pray the Father, and he shall give you another Comforter (Paraclete), that he may abide with you for ever"
John 15:26 "But when the Comforter is come, whom I will send unto you from the Father, [even] the Spirit of truth, which proceedeth from the Father, he shall testify of me"
John 14:26 (NRSV) 26 But the Advocate, the Holy Spirit, whom the Father will send* (will send to come, not already here) in my name, will teach you everything, and remind you of all that I have said to you.
John 16:7-14 "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. And when he is come, he will reprove the world of sin, and of righteousness, and of judgment: Of sin, because they believe not on me; Of righteousness, because I go to my Father, and ye see me no more; Of judgment, because the prince of this world is judged. I have yet many things to say unto you, but ye cannot bear them now. Howbeit when he, the Spirit of truth, is come, he will guide you into all truth: for he shall not speak of himself; but whatsoever he shall hear, [that] shall he speak: and he will shew you things to come. He shall glorify me: for he shall receive of mine, and shall shew [it] unto you."
John 1:19-27 19 Now this was John’s testimony when the Jewish leaders[a] in Jerusalem sent priests and Levites to ask him who he was. 20 He did not fail to confess, but confessed freely, “I am not the Messiah.” (note this would be Jesus) 21 They asked him, “Then who are you? Are you Elijah?” He said, “I am not.” “Are you the Prophet?” (so, who is that prophet)
Luke 3:16 16 John answered them all, “I baptize you with[a] water. But one who is more powerful than I will come, the straps of whose sandals I am not worthy to untie. He will baptize you with the Holy Spirit and fire. (will come – Jesus was already here)
Mark 1:7 7 And this was his message: “After me comes the one more powerful than I, the straps of whose sandals I am not worthy to stoop down and untie.
Some of the above verses, the word "comforter" is translated from the word "Paraclete" ("Ho Parakletos" in Greek). Parakletos in Greek is interpreted as "an advocate", one who pleads the cause of another, one who councils or advises another from deep concern for the other's welfare (Beacon Bible commentary volume VII, p.168)
original Greek manuscripts speak of a "Holy pneuma." The word pneuma {pnyoo'-mah} is the Greek root word for "spirit." There is no separate word for "Ghost" in the Greek manuscripts, of which there are claimed to be over 24,000 today.
John 14:26 is the only verse of the Bible which associates the Parakletos with the Holy Spirit. But if we were to go back to the "ancient manuscripts" themselves, we would find that they are not all in agreement that the "Parakletos" is the Holy Spirit. For instance, in the famous the Codex Syriacus, written around the fifth century C.E., and discovered in 1812 on Mount Sinai by Mrs.Agnes S. Lewis (and Mrs. Bensley), the text of 14:26 reads; "Paraclete, the Spirit"; and not "Paraclete, the Holy Spirit.".
A "Spirit" in the New Testament is a human Prophet. Therefore, Jesus had predicted the coming of a human Prophet (spirit) after him and not the Holy Spirit. Jesus would not have used the word "he" for the Holy Spirit. He would have used "it" instead in John 14:26 above.
Read 1 John 4:1-3 below:
"Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world," (1 John 4:1-3)
1 Corinthians 2:10 (NRSV) 10 these things God has revealed to us through the Spirit; for the Spirit searches everything, even the depths of God.
2 Thessalonians 2:2 (NRSV)2 not to be quickly shaken in mind or alarmed, either by spirit or by word or by letter, as though from us, to the effect that the day of the Lord is already here.
Does the Holy Spirit "speak" or "inspire"
The Greek word translated as "hear" in the Biblical verses ("whatsoever he shall hear, that shall he speak") is the Greek word "akouo" {ak-oo'-o} meaning to perceive sounds. It has, for instance, given us the word "acoustics," the science of sounds. Similarly the verb "to speak" is the Greek verb "laleo" {lal-eh'-o} which has the general meaning "to emit sounds" and the specific meaning "to speak." This verb occurs very frequently in the Greek text of the Gospels. It designates a solemn declaration by Jesus during his preaching (For example Matthew 9:18). Obviously, these verbs require hearing and speech organs in order to facilitate them. There is a distinct difference between someone "inspiring" something and him "speaking" something. So, the Paraclete will "hear" and "speak," not "inspire."
The Holy Ghost was already with them
In the above verses we read "if I go not away, the Comforter will not come unto you; but if I depart, I will send him unto you." The comforter cannot be the Holy Ghost because the Holy Ghost (according to the Bible) was "with" them already (and even quite active) long before the coming of Jesus himself and then throughout his ministry. Few example.
Genesis 1:2 "And the earth was without form, and void; and darkness [was] upon the face of the deep. And the Spirit of God moved upon the face of the waters."
1 Samuel 10:10 "And when they came thither to the hill, behold, a company of prophets met him; and the Spirit of God came upon him, and he prophesied among them."
1 Samuel 11:6 "And the Spirit of God came upon Saul when he heard those tidings, and his anger was kindled greatly."
"Then he remembered the days of old, Moses, and his people, saying, where is he that brought them up out of the sea with the shepherd of his flock? where is he that put his holy Spirit within him?" (Isaiah 63:11)
"For he (John the Baptist) shall be great in the sight of the Lord, and shall drink neither wine nor strong drink; and he shall be filled with the Holy Ghost, even from his mother's womb." (Luke 1:15)
"And the angel answered and said unto her, The Holy Ghost shall come upon thee." (Luke 1:35)
"And it came to pass, that, when Elisabeth heard the salutation of Mary, the babe leaped in her womb; and Elisabeth was filled with the Holy Ghost" (Luke 1:41)
"And his father Zacharias was filled with the Holy Ghost, and prophesied, saying," (Luke 1:67)
"And, behold, there was a man in Jerusalem, whose name was Simeon; and the same man was just and devout, waiting for the consolation of Israel: and the Holy Ghost was upon him." (Luke 2:25)
"And it was revealed unto him by the Holy Ghost (Simeon), that he should not see death, before he had seen the Lord's Christ." (Luke 2:26)
"And the Holy Ghost descended in a bodily shape like a dove upon him (Jesus), and a voice came from heaven, which said, Thou art my beloved Son; in thee I am well pleased." (Luke 3:22)
"Then said Jesus to them again, Peace be unto you: as my Father hath sent me, even so send I you. And when he had said this, he breathed on them, and saith unto them, Receive ye the Holy Ghost." (John 20:21-22)
Did they or did they not already receive the Holy Ghost? Was Jesus not still with them when they received the Holy Ghost? Was the Holy Ghost not with Simeon, Mary, Elisabeth and Zacharias before the birth of Jesus? Was the Holy Ghost not with Moses when he parted the seas? There are many more similar verses to be found in the Bible. In the above verses, we are told that if Jesus does not depart then the parakletos will not come & another. Thus, the "Holy Ghost" cannot be the one originally intended since it was already with them. The contradiction is quite obvious.
Jesus is also a Paraclete / advocate / comforter
1 John 2:1 (NRSV) 2 My little children, I am writing these things to you so that you may not sin. But if anyone does sin, we have an advocate (parakletos) with the Father, Jesus Christ the righteous;
Matthew 21:11 NRSV) 11 The crowds were saying, “This is the prophet Jesus from Nazareth in Galilee.”
Luke 24:19 (NRSV) 19 He asked them, “What things?” They replied, “The things about Jesus of Nazareth,[a] who was a prophet mighty in deed and word before God and all the people,
"He" not "It" Notice the use of "he" when referring to the Paraclete and not "it." If we read John 16:13, we will find no less than SEVEN occurrences of the masculine pronoun "He" and "Himself." There is not another verse in the 66 books of the Protestant Bible or the seventy three books of the Catholic Bible which contains seven masculine pronouns, or seven feminine pronouns, or even seven neuter genders. So many masculine pronouns ill befits a ghost, holy or otherwise. The word "Spirit" (Greek, pneu'ma), is of a neutral gender and is always referred to by the pronoun "it."
John 16:13 (NRSV) 13 When the Spirit of truth comes, he will guide you into all the truth; for he will not speak on his own, but will speak whatever he hears, and he will declare to you the things that are to come.
1 John 4:6 (NRSV) 6 We are from God. Whoever knows God listens to us, and whoever is not from God does not listen to us. From this we know the spirit of truth and the spirit of error.
This is also likely to be linked to Deuteronomy 18:18 The Prophet like Moses – see link https://hermeneutics.stackexchange.com/a/60730/33268