Would this be tier 0?

[ryu]

Doesn't matter - calling Pazuzu is not listed on Paladin's list of class abilities. Furthermore, Candle of Invocations is not his class ability either. It is abuse of external entities and items - any lucky commoner can do the same (with some Aid another and circumstance bonuses).

And that matters even less. Is Pazuzu more likely to work for paladins yes or no? That's the only relevant part of the discussion.