It is a formulistic error of the Jehovah’s Witnesses that Christianity is based on the Scriptures. For that to be the case this would mean that Christian doctrine could not exist until Scripture was written.
Remember that the Christian congregation or Early Church was alive and functioning before any New Testament text was composed. Christians already had a concept of what the “spirit” was and how it fit into their religion, and it was this that defined what they wrote.
But accepting that the context of Scripture gives the real meaning would be accepting the JW formula that Scripture defined doctrine. For that to be the case, then there would be no faithful Christians to write any of the New Testament texts because until there were those texts there could be no doctrines to produce Christians in the first place. And if there were no faithful Christians following a Christian religion in the first place, then there would have been no one to write the New Testament texts you cite.
Therefore the texts cannot be read alone as in a vacuum as the Watchtower tells us they should. Instead one has to develop another formula in order to provide reliable exegesis.
The formula one should follow to understand what the “holy spirit” meant to Early Church writers as they composed the New Testament texts should be something like this:
1. Determine why such writing was chosen to be added to the New Testament canon over others.
2. Demonstrate how the text came to be in the form now recognized as canonical.
3. Place the writing in its historical, cultural, and linguistic setting.
4. Compare the text to any extra-Biblical traditions and compositions available.
5. Trace current exegesis regarding texts back to their origins and compare them to the most ancient regarding the same.
Why You Can't Just Use the Context Alone
If you don’t follow this formula and just attempt to read and interpret Scripture by its context only, you will end up with inaccurate conclusions. To demonstrate:
The Gospel writer takes liberties with the way he quotes the Hebrew Scriptures in many places in Matthew. For instance, at Matthew 2.23 the author states: “…so that what has been spoken through the prophets might be fulfilled, ‘He will be called a Nazorean.’”
Some have gone to great lengths to explain this by merely the context, claiming everything from this being an ancient prophecy that once appeared in the Hebrew text but was erased to similar things based on lost Greek readings from the Septuagint.
But if you place Matthew in its historical, cultural, and linguistic setting, and you take into account its Jewish background and Judaism’s traditions, the text makes sense. Matthew is employing “midrash.”
The technique is quite foreign to most Christians, and alien to Gentile cultures in general. It is a means of teaching a text by the way you quote it. Since Hebrew is very terse, one can focus on a particular shade of meaning and build a teaching on it even though this changes the Scripture considerably from its original wording.
40-Year Old Steve Carell or a Maiden or a Young Woman without Carnal Knowledge?
Matthew does this a lot. At 1.23 he alters the Hebrew and Greek word for “maiden” and creates a play on words on the dual Semitic meaning of “virgin,” i.e., a “young woman” and “one that has never had sexual relations.” The original Hebrew text at Isaiah 7.14 doesn’t technically describe a woman lacking carnal knowledge, and the Greek LXX version of the same text refers to the type of “women” who were generally virgins as well as being youthful. Via midrash, Matthew combines the meanings to fit his theology that the “virgin” birth was prophesied, even though there this is not the literal, original meaning.
Using the same technique, Matthew “quotes” Judges 13.5, Isaiah 11.1 and 60.21 as if it was a single text, using the same “play-on-words” midrashic technique, and sees this “text” fulfilled in Jesus, claiming that Jesus was foretold to be a "Nazorean."--Matthew 2.23/
But if the texts don’t really read this way, how can Matthew say they were “fulfilled” in Jesus? That’s what midrash does. Matthew isn’t saying that individual texts proclaimed Jesus as the promised Messiah. Via midrash Matthew is claiming that all the prophets, in way or another, testified to Jesus. His “made up” texts, so to speak, are within allowable Jewish exegetical techniques of the time.
If you ignored the background and traditions that the surrounded this gospel’s composition, these texts would be difficult to decipher and explain. Therefore one needs to ignore the Watchtower technique of accepting a “first blush” reading of texts and employ a more critical approach.
Employ a Critical Formula
While I will not attempt here to re-write you conclusions, I will say this: based on a more critical approach the New Testament texts suggest that texts were chosen for canonization (and even redacted) to fit a somewhat more complex and developed doctrine of the Holy Spirit than you suggest, and not the other way around.
It might help to investigate the liturgical use of the texts in the centuries leading up to the final canonization and see if alternate pericopes from competing texts about the spirit existed, and why particular ones were chosen over the others in the canon’s finalization. This will help you sharpen your conclusions.