ok even iff all priestess where high enough still got a G-O
becausse they still whent for unification
It isn't just a matter of having people like you, you actually have to convince them how to vote. Having them like you generally means they're more likely to listen to you, but it doesn't guarantee any given vote.
The second day game over is determined by a specific variable just for this decision. Mind you this is just for avoiding the gameover as far as I can tell. You need it to be 0 or LESS. You also gain 1 sarai influence for having less than -5.
The game starts with 3 points in favor of the decision.
Things that affect the decision:
Betricia will always remark that the churches strength lies in diversity: -1
Having Sarai try to convince Nabith specifically: -1
Having Sarai go all out: -3
Not having Sarai use influence: -1
Argue for alternate unity (with Esmera's deal): -1
Argue for alternate unity (without Esmera's deal): +1
Argue about who will lead and Annah will change her mind: -2
Don't argue about who will lead and Annah will support the idea: +1
Agreeing to both Esmera and Keranni's deal (they'll both be pissed): -1
Agreeing to Esmera's deal without accepting Keranni's deal: -1
Agreeing to Keranni's deal without accepting Esmera's deal: +1
Not agreeing to either person's deal: +4
Getting Jhenno's help: -2
Helping the Order of Silence at all earlier in the game: -1
Helping the Order of Silence as much as possible earlier (not cumulative): -3
Don't have Sarai convince Nabith specifically and don't argue about church unity: +1
Most of the other options affect the overall score of the council which can affect other decisions and outcomes or individual high priestesses influence.
I might need to edit this, because I'm not 100% certain on it just yet, but it's close. Some numbers might be one point off here or there (and some of it might change a bit in balancing patches). The actual event is convoluted as all fuck (as are all the church decisions in this place. The sheer amount of work going into these things is huge.)
It's worth noting that most of the decisions also have other effects, like making someone feel indebted to you, turning someone against you, or changing someone's influence a little.