You already know they and the Laésa tend to negotiate rather than shoot each other. To be clear, they aren't always exactly always friendly to one another, they try to recruit the same kinds of people and both claim pieces ot Tarislar as their own. But a full-out war, even if one side 'wins' (and in case of violence, that'd most likely be the Ancients), the result would be a lot of dead elves which would still be a defeat for the Ancients and could end up costing them a lot more than they stand to gain from being rid of the Laésa. So other than some occasional clashes between small groups of gangers, negotiations and trying to keep out of each others way seems to be the default stance.
Other than that, though, the Ancients aren't exactly known to make deals. They've got more numbers, guns and magic than anyone else and generally have no problems taking what they want. Which doesn't mean they can't be reasoned with, the difficult part is getting in touch with someone far enough up their leadership with have the power and authority to negotiate, before a group of 'lower ranking' elves decides they'd rather just fight you than point you in the right way.
