Assuming I am isekaied to the mission without any access to aether (magic in FFXIV's setting), then I am heavily screwed as I am a puny 34 inch tall Lalafell. I cannot carry heavy loads, I am too short to sit in the driver's seat of a car and reach the foot pedals, etc.
I will almost certainly fail and die in every scenario except 1 and 3. I don't see how I'd change the tide of battle in 3, as the other people in the setting would be far more familiar with space combat and the tech and how to best use it for Earth's advantage.
So I go with scenario 1. I may or may not be able to pilot certain ships. I don't think I'd be able to pilot an X-wing without the cockpit being modified for me, and there is no reason to think why the Rebel Alliance would bend over backwards for me and render the X-wing unuseable for other pilots when they can just have another pilot fly it. I could fly other ships like the Millenium Falcon (doesn't seem to have footpedals) so if I can acquire a ship like that, that'd be good. Or maybe I could be a co-pilot or a turret gunner, or an engineer.
I'd accel at stealth missions with my small silhouette, so maybe I join boarding parties and scouting forces.
If I get to keep my access to aether, then I think I could pretty comfortably take all 5 missions. Magic in FFXIV is pretty insane, letting you create a personal forcefield that deflects bullets in lore, teleportation, etc.