Hi Gena,
1Cor 15:28 When all things are subjected to Him, then the Son Himself will also be subjected to Him who put all things in subjection under Him, that God may be all in all.
What it means to me "that God may be all in all" is that all beings both human and angelic will have been brought out of their carnal state and into oneness with the mind of God.
Now all of the human race will have been changed to spirit and brought into the kingdom. This seems to be where you are confused.
Everything is spirit, and we will be in the 'ALL IN ALL', SO I was thinking it in more," mystical, ghostly, misty, kind of a thing", terms. We would be IN HIM.
Just because all beings will be all in all with God, I think the universe and earth will still be here, the physical realm will not disappear. I think the physical and spiritual realms will still exist together, like now.
To think about what it will be like in spirit, it may help to think about what Jesus Christ was like after His resurrection, we will be like Him.
Luke 24:36 As they were talking about these things, Jesus Himself stood among them, and said to them, "Peace to you!"
v.37 But they were startled and frightened and thought they saw a spirit.
v.38 And He said to them, "Why are you troubled, and why do doubts arise in your hearts?
v.39 See My hands and my feet, that it is I Myself. Touch Me, and see. For a spirit does not have flesh and bones as you see that I have."
v.40 And when He had said this, He showed them His hands and His feet.
v.41 And while they still disbelieved for joy and were marveling, He said to them, "Have you anything here to eat?"
v.42 They gave Him a piece of broiled fish,
v.43 and He took it and ate before them.
In this passage Jesus Christ manifested Himself in the physical form of a man, He said He was flesh and bone and He ate. I think this will be the same for those who are in the resurrection. They will be in glorious spirit bodies, but will be able to manifest into physical form as need be, to relate to those that are still living on earth.
1John 3:2 Beloved, we are God's children now, and what we will be has not yet appeared; but we know that when He appears we shall be like Him, because we shall see Him as He is.
Being all in all with God, thought it will be a spiritual bliss, we will still be individuals with our own personality. We will have been shaped and molded into the image of God, but we will still be the unique indidviduals that our experiences and lives have created.
This is what I think, hope it helps
mercy, peace and love
Kat