You seem to have a lot of the world building established, older fed races are fiscal sticks in the mud, first series of Human interstellar craft are designed for rapid production without compromising function which means a compromise in aesthetics, Elyrans (and presumably other races) have a very mixed bag of technology, they have FTL (though that is mostly bought/borrowed tech because of location) but they also still use vacuum tubes, technological commercialism hasn't set in yet for them so PCBs and integrated circuits are expensive. seriously though with their tech level, they almost certainly have to trade for their space tech, and trade they are apparently very fluent in, because in addition to their planets being in the path of major trade routes, they were able to take advantage of this fact significantly enough to afford the ships they sent in the expedition, yes they saw it as largely a military/defensive endeavor combined with religious sentiment, but the fact is, they didn't have to divert resources from other projects, or at least didn't have a problem diverting them. Dravidians are practical and pragmatic, reside mostly near inner rim, have a satellite beacon project, logical but perhaps a little too unadventurous. Dixx are skilled combatants and can fly also have a reforestation project that they postponed for Earth mission. Arachnians are closer to crabs and diverted resources from Ice towing project that is meant to counter drought, Erocii are terraforming a planet that will bring large amounts of refined metals and other commerce. Of course a lot of this is stage setting, but still. Even with human phase wave/radio assistance, not even the satellite beacon project should take much of a back seat to the war, the Ice towing and reforestation projects are essential for healthy populations that can help fuel the effort, the metal from terraforming and money from tourist and commercial trade can bolster efforts, and navigation is essential as even though Earth ships don't need the assistance, they wont be involved in every mission and other fleets do need the help. My guess is some of the Earth fleet is sent to aid in those projects to strengthen diplomatic relations, as well as for the strategic value.

I also would bet that the first new earth ships to stop being blocky will be the fighters and "carriers" or as I would consider them, troop transports, when I read it I was curious why they bothered retrofitting those rather than flat out replacing them, other then the catapult that i am surprised isn't an electromagnetic ram (unless it's for the BSG imagery) there really isn't much of an advantage oh wait the entire fighter/shuttle bay is the catapult- allowing for formation launching- clever but then they would have to be oriented for the "down is out" problem , and considering how quickly they built the fleet, it wouldn't take long to do, perhaps even LESS time then it took to modify them after all, fighters are generally built around their propulsion systems, the only other advantage I see (other than the Seeker version of Earth FTL) is not needing to make significant alterations to the flight deck and hangars. The main payoff I see for that choice is the allusion that without a launch assist system, launch before ship-maneuverable is not possible. Its neat but really it was just the shell of the Shrike fighters that carry over. come to think of it, the only explanation I can think of, is that at the time of the Seeker Mission, fighter production hadn't been at full force yet, and none of the new fighters could be diverted to Seeker because they are produced too far away, and newer ships were overtaking the demand. Still the look of the ships can serve morale purposes...