The Shroud, the Placard, the Spear, the Grail, the Sword and the Coins are not Outsider specific artifacts. They just happen to be effective against everything -- as Dresden notes about the Spear. He says, it was more real than everything else, it was not just a spear -- it was a spear against everything. Nicodemus intended to use the pseudo-Shroud to start a plague when we first met him. I think it more likely that they are all-purpose items.
As for JC being a Star Born -- I dunno, it doesn't seem like the timing works out, every 666 years or so from 4 BC means Star Born cycles at 662AD, 1328AD and 1994AD. Dresden (and Butcher) are GenX'ers to the core and so the timing is off by several decades, regardless of whether you use 7BC, 4BC or 1AD for the birth of JC.
As for JC being Nemfected, that seems unlikely. JC is a person of the Trinity, so the HS and the Father would also be Nemfected. Whether you personally believe in God, clearly that being is "real" for purposes of the Dresdenverse and according to the Nicene Creed -- the Father and the Son are of the same substance:
We believe in one God,
the Father, the Almighty,
maker of heaven and earth,
of all that is seen and unseen.
We believe in one Lord, Jesus Christ,
the only Son of God,
eternally begotten of the Father,
God from God, Light from Light,
true God from true God,
begotten, not made,
consubstantial to the father
Through him all things were made.
For us and for our salvation
he came down from heaven:
by the power of the Holy Spirit
he became incarnate from the Virgin Mary,
and was made man.
For our sake he was crucified under Pontius Pilate;
he suffered death and was buried.
On the third day he rose again
in accordance with the Scriptures;
he ascended into heaven
and is seated at the right hand of the Father.
He will come again in glory to judge the living and the dead,
and his kingdom will have no end.
We believe in the Holy Spirit, the Lord, the giver of life,
who proceeds from the Father and the Son.
With the Father and the Son he is worshiped and glorified.
He has spoken through the Prophets.
We believe in one holy catholic and apostolic Church.
We acknowledge one baptism for the forgiveness of sins.
We look for the resurrection of the dead,
and the life of the world to come. Amen.
Personally, I do not believe that Angels are contained within the Placard, Shroud, Grail or Spear. There are Angels in the Swords, just as there are Demons in the Coins. I don't think an imprisoned (willing or otherwise) being is required to make a potent artifact. I'm fairly sure that no Demon resides in Marcone's butterfly knife, which he successfully used on Ethniue, it worked because Marcone has Infernal sponsorship. (Plot hole for BG: Why didn't Harry use Soul Fire on Ethniue?).
