Later Christianity is certainly presenting the texts of early Christianity with "Holy Spirit" capitalized as a name.

In the references you sent, the earliest text is the Odes of Solomon (if known only from a later copy). The translation offered was this:

"And the name of the Father was upon it; and of the Son and of the Holy Spirit…"

The most recent scholarly translation of Ode #23 presents it this way:

"And (the tablet) was backed up with the authority of the Father, and of the son and of the spirit of holiness…"

What is the 'spirit of holiness' or the 'spirit of the Lord'? Is it a named personality of God?

It's not so clear.