Good questions. The obvious answers are that God knows the time because he’s God, Jesus doesn’t know the time because he isn’t God, and the holy spirit isn’t mentioned because it isn’t a person.
A related passage that is interesting to consider is Revelation 14:14-16
14 I looked, and there before me was a white cloud, and seated on the cloud was one like a son of man with a crown of gold on his head and a sharp sickle in his hand. 15 Then another angel came out of the temple and called in a loud voice to him who was sitting on the cloud, “Take your sickle and reap, because the time to reap has come, for the harvest of the earth is ripe.” 16 So he who was seated on the cloud swung his sickle over the earth, and the earth was harvested.
Consider what is going on here. The “son of man”, traditionally viewed as an angelic figure in Judaism of the period, is identified as Jesus in the NT. The text says “another angel” came with a message for “the son of man” from God. Some commentators point out the implication that indeed “the son of man” is an angelic being who is here approached by “another angel”. And what message does the angel bring to the angelic “son of man”? He announces that the time for the harvest has arrived. In other words God conveys to Jesus that the time of the end has arrived by means of an angel entrusted with this message, which is in harmony with Jesus’s own words you quoted that only the Father knows the time, not the angels, nor even the Son, until God reveals it.
In turn this comports with Revelation 1:1 which speaks about a revelation which God gave to Jesus in order to share with John. Again this demonstrates definitively that God is greater in knowledge than the Son because he shares his knowledge with him. In John 8:28 Jesus also states plainly that he says the things the Father taught him, again showing that God is superior in knowledge to Jesus. It is such a clear teaching in the NT and a huge problem for the Trinity doctrine which teaches that God and Jesus are equal in knowledge.