Yes, they are fixed in the state of their judgment at the outcome of their trial, some fixed in righteousness, and others fixed in unrighteousness, as we all will be fixed in the state of judgment from judgment day.
Well, the NT reveals that God chooses to show forth his glory
through the glorification of his Son, who with his own life shall purchase from condemned mankind (
Romans 5:18) a remnant to be God's own
personal inheritance (
Psalms 33:12;
Ephesians 1:18) and
treasured possession (
Exodus 19:5;
Deuteronomy 7:6,
Deuteronomy 26:18;
Malachi 3:17); i.e., the church, which is his body, the fullness of him (
Ephesians 1:22-23),
God counting himself incomplete (!) without his inheritance and treasure.
They would be the spirits of the deceased saints, both OT and NT.
Are not the angels complete and fixed in their growth, just as we will be at the resurrection in our glorified, sinless, perfect bodies of eternity?
And at this point, would not the fulfillment of the plan concerning them be their ministry and care of the saints?