Great discussion so far! I ❤ it.
Not sure how feasible an efficient scrapping of a vessel would be, at least initially though its certainly a viable proposal at its core.
In regards to the Aliensverse the
USS Esmerelda (the Aliensverse ship) is classified as an "Light Assault Transport" or whatnot and is the only Colonial Marine ship that had a lot of widely available information on it on the interwebs. There's presumably far more formidable ships but... its what we got. The idea of making the
Esmerelda a transport is perfectly reasonable as it is a large vessel, highly automated and expressly built as a transport. There are two thousand colonists in "hypersleep" on board the vessel as well, so they'd have to be transported elsewhere. The advantage of the
Esmerelda (or just what made it different) is that its self contained with no fleet dragged behind it and has two thousand colonists ready and equipped to 'colonize' as soon as a suitable site is found. All of the other fleets are basically refugees. Plus I'm sure the other Migrant fleets have military forces, but a companies worth of Colonial Marines able to be its own task force is a nice asset regardless.
In regards to the Battletech ship, I'd have to crack open
Betrayal of Ideals again but AFAIK I think
McKenna's Pride and Clan Wolverine has the strongest military (at least speaking in quantity, independent of calcs) because a large portion of Clan Wolverine fled with all of their existing (smaller) warships and the like. They also have lots of professional and elite level power armored infantry, companies worth of Battlemechs, squadrons of aerospace fighters, dropships etc as well as the lower civilian castes and a few hundred??? prisoners they saved from the Draconis Combine. They get this because I was making a snap judgment that they were on the weaker end of the spectrum. So they got more "stuff" so to speak. They have a military force and its a fully deployable one at the moment as well.
The Imperial Star Destroyer
Right to Rule might be comparable with its ground force because it has something ridiculously epic like 9700 stormtroopers and dozens of walkers etc etc on board every ISD and this is 'normal full complements' but IMHO Battletech's Army is potentially the most formidable of the bunch.
Really don't have many comments on Mass Effect. I played the games but I never really dived into the background lore and stuff. One of the benefits they could potentially have is that their Migrant Fleet is diverse. All of the Citadel Races have some representation there. Turians, Asari, Hanar, Volus, Elcor, Krogan, Salarians etc as well as species like the Geth and Batarians. Geth notably might have something exceptional to offer, I dunno. Plus the Biotics ability would be spread out amongst some of them.
As for Babylon 5, because they might be assumed to be "lower tier" as well, I gave them one of the
Explorer class vessels as well. An Explorer-class vessel is one dedicated to exploration and its a huge vessel, over six kilometers long. So it'll likely be the largest vessel in the fleet IIRC. It's crew is mostly engineers, technical personnel, diplomats and other explorers, has massive stores and its own limited manufacturing capability. It can also build and deploy jumpgates to enter Babylon 5 style Hyperspace.
That was the other benefit I was pondering. Babylon 5 Hyperspace isn't particularly fast or whatever, but you can still be clever in using it. Jumpgates tend to have built in (tachyon based IIRC) beacons that allow ships in Hyperspace to safely navigate from Jump Gate to Jump Gate. One of the benefits of Hyperspace is the ability to hide in Hyperspace for periods of time, as well as more combat related things like opening a Jump Point (albeit only the
EAS Agamemnon or the Explorer-class vessel would be able to do this) in the midst of enemy forces. Hypothetically, it should be possible for other races to use Jump Gates or follow the EAS Agamemnon or any other Jump Point capable ship into Hyperspace as well as long as they stay close together.
Just another potential advantage to a Flagship/Fleet that might be at an initial disadvantage.
I'm thinking lots of civilian craft that were in Imperial Remnant space that had to flee. Military vessels like the Gozantis and Arquitens were likely not part of the Migrant Fleet that Pelleaon somehow ended up leading to survival. So they might be armed, but it's still going to be pretty small scale. Laser cannons or blaster cannons or a few starfighters bolted to the docking umbilical or something on that level.
When I was looking up the wiki for Galaxy-class starships that showed up onscreen,
USS Venture seemed the most appropriate because it said it was using a TNG era model according to one of the Star Trek wikis. Even if what you say is true, I'd prefer not to use a "War Refit" because the Galaxy-class most everyone is familiar with are the ones that appeared in The Next Generation and a far more well known quantity then just a "War Refit" variant which isn't something that has nearly as much information on it, concrete or otherwise.