Keeping Helpful Enemy Dominion Alive...

[Endoperez]

Hostile Luck: it should work as Misfortune. It only enables bad events in the province in question, doesn't affect the ratio of good and bad events in the empire.
Hostile Magic: It should have no effect on research. I tested it, it doesn't help enemy research.
Hostile Growth: I didn't properly test it, but two of my three inquisitors got old age afflictions in hostile Growth 3 dominion.

Preaching province with Order, Production and Growth from hostile to positive dominion: no effect on income, resources or supplies. Population grew even under hostile growth.

I think this means that Order and Production give full benefits even in hostile dominion, Growth gives full supply and income benefits even in hostile dominion but not old age affliction resistance. Hostile magic goesn't give research bonus and lowers everyone's magic resistance.

This leaves only hostile Luck and hostile negative scales as untested. I presume they are all handled as negative scales.