I have yet to see anything that I would call an imperialistic tendency whenever it comes to Eorzea. Private business firms =/= political stance. Sure, they can influence politics but it doesn't solely mean that a business somewhere represents all of Eorzea. More so now that Ul Dah is moving to making political changes in it's landscape since after the 2.5 fiasco. We shouldn't forget the hand was more or less forced whenever it comes to Ala Mhigo, it just happened at a time whenever Doma also sought to relieve itself from it's Garlean masters. I can see where one might see a move on Ala Mhigo being for gains but not Doma. Doma is it's own government with it's own political system and concerns. It just happens to be that we have the same enemies in the world. Hien was on the right track to receive the Garlean ambassadors regardless of the moves that they made for a hope on peace. Right now Eorzea's primary objective isn't to over throw Garlemald but to sow dissent.
The dissent being the key word as they aren't looking to gain anything but to keep the Garleans from launching an attack while hoping for a revolution. To be honest Eorzea and it's allies could use a break lest they fall to attrition. I don't feel either side can really afford an all out front against the other. I am mostly assuming the move to start an attack from Elidenos is just the normal Ascian route for causing chaos and destruction. Right now Varis cannot do much but to undermine the very plots that he is going to be forced to execute. If it wasn't apparent before, it is now brutally apparent that he is Emperor because the Ascians allow it. They are a stone's throw away from taking it back from him if he does anything to ruin the plans.
As for Hingashi I think they are doing what is best for their well-being. They are a neutral state that trades with all sides, and that is a good position to be in whenever it comes to a time of warfare. If they can provide resources to both sides and stay out of the cross hairs as well then they are set to gain what everyone else is losing. Plus Hingashi is notoriously isolationist with a rough take in the increasing amount of Foreigners in it's territory.