I would begin by saying that the Holy Trinity is the center of my faith, and, as a student of patristics/matristics, it has always fascinated me, from Gregory Nazianzus all the way to Augustine's "De Trinitate".
In my postings on Restoration hermeneutics, I have been trying to urge my kindred to do theology, which, I suspect, is something that must seem kind of scary (or, I gather, "denominational")--since, it would seem, that that somehow equates equaling "experience" w/ "scripture".
I'm not saying that to be mocking, or sarcastic, in the least; it's just become vivid to me that my kindred have a different understanding of how to reflect on Christian living in the light of Holy Scripture. As a DoC, I believe in using my reason AND scripture, to understand God's activity today. Still, the Word of God is pre-eminent, and judges all theological reflection: I'm closer, in fact, to the Wesleyan Quadrilateral: reason, experience, tradition, and scripture. All four work together.
No, I don't know of any of the Restorationist founders using she to refer to the Holy Spirit. I'd bet some women did, though, but their histories tend to get forgotten.....
I said what I did b/ "ruah"--i.e. "spirit"--in Hebrew is feminine; and Proverbs 9 has a decidedly "feminine" turn to it, in picturing the creativity of God. Of course, in Johannine Logos theology the "Word" becomes the creative priniciple of God, and which becomes in classical theology "the Christ"; and Christians identify Christ w/ Jesus of Nazareth; although, as I remind folks at times, the Second Person of the Trinity is not Jesus of Nazareth, but the Christ. Both came together--two natures, one individual--in the historical Jesus, we as Christians believe; hence, the wisdom of Chalcedon in saying the two (2) natures dwelt together, but how, truly, God alone knows.
Why we (rigidly) insist that the Christ should be female, male, or any gender at all, says more about where we're coming from, than any substantive assertion about The Mystery of Three-in-One. Ooops, I just used "substantia"...which sounds like Hebrews 11.1 and God's "substance", which was another mistake of early theology; insisting that God has physical substance, by wedding Greek philosophy w/ the scriptural datum.
Language is power, and referring to the Triune God as she or he, is tricky, for a lot of people. I use feminine language at times, in particular in reference to feminine images of God in the New Testament, which evangelical scholars tend to want to ignore.
Of course, feminist/womanist scholars rightly poke fun at male theologians who insist that "God had to become a man" to save us. Why that is, it seems to me--i.e. insisting on gender as part of salvation-history--is anybody's guess; u/l, the feminist/womanist scholars and theologians point out, the one making that argument is vested in patriarchy and power.
I confess myself orthodox, in particular in terms of classical Christian theology; but, I don't obsesss over gender. Our concerns for it say more about us, and our needs for God. If women can recover the feminine aspects of God and refer to Her, I certainly have no probem w/ that; liberation from patriarchy and self-empowerment.
It would seem to me that a NT people would certainly welcome it, in the Spirit of the baptized community, in which there is "neither Jew nor Greek, male nor female...."