is there a item / permanent spell / summon to make priests stealthy ?

[Graeme Dice]

Originally posted by Boron:
especially marignon DF still has lvl 2 stealth priests + the lvl 4 inquisitors which count lvl 8 for preaching .

They only count as level 8 when in enemy dominion. As soon as the dominion is positive, they go back to level 4 priests.

so you should be able to spread dominion quite quickly to neighboring provinces and because you can bloodhunt you should have access to vampire counts quite quick.

Dominion from preaching does not spread to neighbouring provinces. Only dominion from temples, your prophet, and your pretender does will spread.