Apologies for the thread resurrection, but I figured this was better than starting my own, identical thread.
It's an interesting thought experiment...
What sort of hypothetical survival strategies MIGHT have worked, OTHER than terraforming an earth-type world?
RFC's stance seems to be that most forms of deep-space, sublight probes or habitats would not have been able to escape detection by the Gaba. If we accept that as authorial fiat, what else does that leave?
Personally, I'm a little surprised that no-one tried buried, hostile-enviroment vaults... If Battle Steel can do half the things we think it can, and if the Federation was half as wealthy as they sound like...
I'd be really tempted to try things like building a secret earth-tunneling mini-base, hiding it REALLY unlikely locations, then ordering it to go completely silent for a few hundred years, or even a few thousand.
You could hypothetically land a sealed mini-base on the surface of Venus, tunnel underground, seal yourself in, and then go to sleep for a few hundred years.
It would be a pain to build, and it wouldn't even be guaranteed to ever get back out of Venus's atmosphere under it's own power... but if the hull was thick enough, and anti-corrisive enough, it might be able to survive a one-way landing trip. Getting back out in 500 year's is the PICA's problem.
Likewise, you could try hiding an aerostat deep inside the atmosphere of Jupiter, or a submarine at the bottom of the Marinas trench, tunneled into a hide-away dug into the side of the trench wall.
You could drop something down into the seas of Ganymede, or the Methane Lakes of Titan. or the Ice-Crust of Europa.
And of course, if you successfully hide ANYTHING dormant for a few hundred years, then you have an entire range of options for what you want to bet your lives on when it finally wakes up...
Do you rebuild in your current hidden location, or make a break for it?
Cryosleep humans, PICA'S, Virtual Humans, or pure AI's? Lab-grown humans from stored DNA profiles?
Sublight stealth or hyperlight running for it?
Hundred-year time-scales, or Thousand-year, or even million-year? how long do you want to run or spend rebuilding, before you risk announcing yourself to the Gaba again?
Smallest possible Von Neuman Probes, or largest possible stealthy factories?