"In" the Person of Jesus? No. I am saying that Jesus is the complete revelation of God to man. The Father and Spirit are not revelations of God. Jesus is. God (the One True God) became man and revealed Himself to us. I am saying that there is nothing to know of God that has not been revealed through Christ. What is mystery is so because of the limits of our understanding, not because the fullness of God did not dwell in Christ.
I think that what Y1 (and I) are concerned about is that you seem to be concentrating on the Oneness of God (with which I fully agree) at the expense of His Threeness.
We can agree that the Lord Jesus is the perfect expression of God (John 1:18). But it is equally true that the Father sends the Son (John 5:23-24); came from Him (John 16:28); returns to Him (John 14:12); receives His commandment (John 10:18); does His will (John 4:34; 6:38); addresses prayer to Him, using the word 'You' as He does so (John 11:41; 17:3; 12:27-28) and speaks of Him as 'He,' 'Him' and Himself' (John 5:19-26).
The Father speaks
to the Son, addressing Him as 'You' (Mark 1:11; Luke 3:22); He speaks
of the Son, speaking of him as 'Him' (Mark 9:7), and gives an audible reply to one of His prayers (John 12:27-28).
If we read John 14:16, 26; 15:26; 16:13-15, we find that the Comforter, the Holy Spirit is also a distinct Person. Jesus asks the Father to send Him; the Father sends Him in the Son's name; Jesus sends Him from the Father. The Spirit glorifies the Son and takes what the Father has given to the Son and shows it to the disciples.
In Matthew 3:13-4:1, at the baptism of the Lord Jesus, we see the Trinity and are made aware of the distinction between the Persons; the Son on earth, the Father in heaven and the Spirit descending. There is also the baptismal formula of Matthew 28:19.
All these things show that the Persons of the Trinity are distinct Persons. The Son is not the Father; the Father is not the Son, and neither of them is the Spirit, although there is only one God and that God is not divided. By 'Persons' is meant that there are personal self-distinctions within the divine Being, who use of themselves the word 'I' and of each other the words 'You,' 'He' and 'Him.'