I'll take a moment to comment on the core relationship. It's interesting that it's sort of a role reversal of X's 'romance', it's
Squall who is forced by 'fate' (which, sort of akin to
Interstellar, turns out to be a fate of his own design, thanks Causal Time Loops!) to be burdened with an awful task. I also kind of like that Rinoa isn't 'special' in any plot relevant way, that she's just someone who becomes meaningful to Squall by her own character and ability...Although, isn't there a bit of an issue that Squall X Rinoa might be a little... incestuous?
I think Edea might be the longest I've played as a Guest Character in any FF. Sephiroth was a glorified cutscene in VII, Seymour was a single battle in X, and I think Beatrix was only one sequence in IX. I'm not sure how long Leo is in your party in VI, and I'm unsure how long Vossler and Larsa are playable, but I still think Edea might be the longest.
Also hahaha I only yesterday at work realized why Irvine lost his nerve to take the shot; he hadn't forgotten she was his foster mom.
I also find it amusing that all PS1 era FFs involve space in some way (FFIX's is a bit abstract but it's still there). I know FFIV involved space as well, but I find it funny that all PS1 ones involved it but none have since. Unless you consider Cocoon a 'Moon' of Gran Pulse ersumshit. Speaking of space, the Esthar Mass Driver/Railgun Space Center is so fucking cool.
I love Esthar so much, the reveal of the entrance is just fantastic. Now I am going by memory here, it's been a while. But I don't think Esthar was ever out to conquer Galbadia, they were going about another mission for the Sorceress, which included that dig site Laguna blundered into. You'll find out about that real soon.
Galbadia wasn't happy with them waltzing into their country like they owned the place and was resisting. To Esthar, Galbadia was almost irrelevant at the time. If certain things had happened as the Sorceress planned, they would have eventually crushed everyone. It makes Galbadia's ambition to become a superpower a bit pathetic really.
Yeah my headcanon is that Galbadia took effective control of its continent under the pretense of uniting the world against Estharian Tyranny; once the war ended they still used the fear of the Sorceress (who the denizens of the Galbadian continent don't know has been shot into space) as a flimsy excuse for maintaining dominance of the continent.
Also my mind went to horrible places with all the talk of Esthar being Xenophobic and Isolationist. I'm now imagining Laguna with a 'Make Esthar Great Again' hat complaining about 'Crooked Adel' and getting chants of 'Lock Her Up'! I'm sorry, I'm so sorry.