It's Cairhein, there always will be plots, assassination attempts and political machinations going on, it's in their blood and it's natural to try to test Elayne's mettle at first. But it's logical to assume that with a strong ruler on the throne, supported by the Dragon Reborn, there will be less of this kind of activity than while the throne remains empty.

Colavaere assassinated her main rivals to get the Sun throne, Elayne didn't killed anyone to do it.

None of this was by force, except the parts of Murandy, which wasn't done by Elayne. Also you're thinking too much in modern terms, not in terms of a feudal society. Aliandre swearing fealty to Perrin who was made an Andoran lord doesn't make Ghealdan part of Andor. This is not how the things work in a feudal society. Cairhien won't become part of Andor either, it would remain a separate nation with its own nobles, which will share a monarch with Andor. Faile explains it as a pack of nations (Andor, Cairhien, Two Rivers, Ghealdan, even Mayen and Saldae are suggested), in which Elayne will be the leader, but not an absolute monarch by any means and each nation retains a lot of autonomy to a different degree.
The Seanchan have far tighter control on their territories and the other main difference is that Andor hasn't try to conquer anyone by force under Elayne's leadership.