Rev 12 tells us that Michael has authority over angels (no one else but Jesus has such authority).
Nowhere in Revelation does it say that only Jesus had authority over angels, that certain angels weren't ranked above others. That is precisely what is presumed by the term archangel in apocalyptic literature, a class of angels ranked over all others.
Genesis 3:15 tells us that Jesus, the seed would crush Satan.
Actually it says no such thing, but this is a later interpretation which may or may not be relevant to Revelation 12. You are adding to this your own interpretation that the battle in heaven is the "crushing" of Satan, as opposed to his defeat and binding by Jesus in ch. 19-20, or Satan being thrown into the lake of fire afterwards. In ch. 12 Satan has only lost his place in heaven, he is depicted as coming to earth, setting up a political and religious structure (the two Beasts), breathing his own authority into them, whereby he misleads the entire world (ch. 13-15, 17).
Jude 9 tells us that Michael is the archangel.
But not necessarily the only one.
Thess 4:16 tells us that Jesus has an archangel's voice.
It says no such thing. It says that while Jesus descends from heaven, there will be a shout, an archangel's voice, and the sounding of a trumpet. Three sounds accompanying the descent. It doesn't say that Jesus' voice is like that of an archangel.