The question was asked, “Where were Jesus Christ and the Holy Spirit when Michael was fighting Lucifer” at the beginning? The short answer is that both Christ and the Spirit were in the bosom, the Divine Heart, of God the Father as They had always been.
The question was asked, “Is the Holy Spirit Michael?” The answer is in the negative. The Holy Spirit is God by nature, the love between God the Father and God the Son, Jesus Christ, so He is the third Person of the Holy Trinity – an uncreated Person. The Archangel Michael is a created being, a lowly angel who became the prince of the heavenly hosts because of his utmost fidelity to God.