hmm i would imagine the wealthy trait, for a gold influx to pay for treaties. once you have some basic treaties and a reasonable military they won't attack you.
Yes, I had wealthy, and it certainly helped. But on ridiculous, the AI starts with more than 100000 Gildar, so wealthy will not keep them off your back, and neither will a few archers.
How many volcanoes spontaneously erupted?
None. If I harmed the AI is any way, it's by making a cordon of troops to prevent Yithril from wiping off Pariden, and by boxing in Gilden in a corner of the continent, which was more or less unintended.
Paid off the Trogs to kill everyone for you.
Nope. By the time I had scouted them, bribing someone to go to war would have been probably too expensive. In any case, I did not start any wars, by proxy or otherwise. Everyone jumped on poor Porcupine and I had to save her scrawny ass by getting in the Empires way.