They are the same thing: % chance for enemies killed to explode for 25% of their maximum life for chaos damage. Profane Bloom has stipulations on which enemies get the chance applied to them but it is still the same effect.
As such they stack additively.
You would have a 45% chance for cursed enemies you kill to explode, a 20% chance for non-cursed enemies you kill to explode, and a 25% chance for cursed enemies your minions kill to explode. They explode for 25% of their maximim health in chaos damage.
This is correct.