I’ll trust the translators of versions like the NASB and ESV. Greek is precise, but it takes some skill to do it right. The folks who did versions like the NASB & ESV had great concern for accuracy, and were not beginners looking at lexicons.
“13When the Spirit of truth comes, he will guide you into all the truth, for he will not speak on his own authority, but whatever he hears he will speak, and he will declare to you the things that are to come. 14He will glorify me, for he will take what is mine and declare it to you. 15 All that the Father has is mine; therefore I said that he will take what is mine and declare it to you.” - John 16
Lots of ‘he’ in that passage...
As for John 14:26:
“He (ekeinov).
Emphatic demonstrative pronoun and masculine like paraklhtov.”
http://www.studylight.org/com/rwp/view.cgi?book=joh&chapter=014&verse=026
New King James: Joh 14:26 But the Helper, the Holy Spirit, whom the Father will send in My name, He will teach you all things, and bring to your remembrance all things that I said to you.
Note that the NKJ says the holy spirit is a "whom".
From your link:
"Whom (o).Grammatical neuter, but "whom" is correct translation."
Why, if they they says it's grammatically correct to say "which" do they translate it "whom"?
Translator bias, plain and simple.
But that matters little because when the holy spirit is present in believers it IS Jesus, or God. So it makes little difference whether you refer to it as "he" or "it".
For example....if I live in on one side of a wall and you live on another and I poke my hand through the wall and knock over your lamp, you would rightly say that it was me knocking over the lamp. However it's just as correct to say that it was my power and my strength that knocked over the lamp. Either way my arm poking through isn't a different person. It was me.
In the same way God "pokes" through in the form of his holy spirit. We know it's him poking through. But it's not a different person up there in the Godhead as I've shown from multiple scripture examples.