Hmm. Well either way, good job with the list.
I also like how the list sums up every race's gimmicks. Spire one makes so much sense that I wonder why I didn't think of "We are too advanced for you to understand why we are doing this bizarre thing" reason xD
Anyway, that does highlight its really hard to think reasons for neinzul and zenith... Zenith are supposed to be friendly after all and since they are the buildings they don't exactly rapidly expand.. I'm not even sure what they exactly want. So main reason for conflicts I can think of are misunderstanding related to their unique nature and population.
With neinzul, well even in AI Wars you don't really know why they are attacking you, but their main interest is their children. Only neinzul faction we know reason for attacking is those who want to avoid resources being spent so that their children may live in future. On diplomatic conversations in Stars beyond reach they are always about "Talk fast" and such because they live only for day so they want to spend their time efficiently.
So yeah, I'm still not sure what would be exact reason for neinzul to attack, but their main thing is protecting future of their children(which is really short term future since they die in a day) and spending time as efficiently as possible. So they would certainly attack if they think your actions will kill their children, but most of actions you could do that belong in that category really show up in the "general reasons" category...