That was a great post touching on a few great points.
"We are God" We're supposed to let God in our hearts. Along this journey more of God is manifested in us till all there is is God. So in that sense we become God. This is why Jesus said if you see me you see God. They became one with each other.
"In the spiritual realm, and then manifested in the physical realm." Everything is first created in the spiritual realm. The physical realm is a shadow of the spiritual realm. If you seek the spiritual realm, you master the physical realm. The shadow will follow freely. That's why Jesus said something like If you seek the kingdom everything will be given to you freely.
And then you talked about sacrifice. Everything in the universe is based on sharing or sacrificing. One smaller part sacrifices or shares for the greater, weather it's a body, plant, or planet. If we live in this manner, we are one with the universe & God. There is no greater act, like you said.
Each one of these methods can acheive oneness. All three together? Certain oneness? I seriously wonder if God's plan is to grow more Gods, or at least more beings like Jesus.