We have to keep it simple and at the same time we have to be able to support what we teach from the scriptures.
I gave you the scriptures. Go back and re-read my posts.
God is Spirit, one Spirit. Jesus also said that the Holy Spirit is the Spirit of the Father. Matthew 10:20, Therefore, because the Father is one Spirit the Holy Spirit has to be His Spirit. Whenever we have more than one spirit in association with God we have more than one God then we are polytheists. The Holy Spirit is distinct from the Father's person/soul, unified like bone and marrow, two distinct elements that are completely one.
These are the scriptures again that shows that God says Himself that He has a soul/person - Isaiah 42:1, Jeremiah 6:8,32:41, Leviticus 26:11. Please read them. The scriptures are only "incomprehensible mysticism" to people who can't understand them. God says specifically in these scriptures that He has a soul, if you deny that you are saying that God is lying.
Anyone who is begotten has to have a beginning at some point. To be eternally begotten is an oxymoron.
"All Three persons in the Trinity dwell in all believers." That is correct, for the most part. All three dwell in the believer. You said God is a person. The person of anyone is the soul. I thought you didn't believe that.