I guess Gaians can be considered as Liberty Rogues in their majority are. They're unorganised, so yes, everyone can be in.
Why Gaians are in Bretonia? As it was mentioned, because Bretonia is the most polluted House, which already "feels" how pollution can damage health and lives of people. So far only BMM bribes and pressure from OS&C stopped Bretonia goverment from satisfying Gaian requirements. Of course with time BMM possibly took some steps to destroy public reputation of Gaians, for example using media: Gaians were accused of many crimes. As result some criminals (possibly even BMM-finansed) joined Gaians and started ruining Gaians reputation. That led to even more agressive actions from Bretonia goverment.
Still, Gaian "sub-groups" in Sigma-13, Texas would be tolerated. Dangerous radio-active scrap is already collected by Junkers for ALG in Sigma-13, and quite liberalistic and caring for it's workers GMG'd allow Gaians to assist them in descreasing pollution in Sigmas. So there'd be no need for agressive actions.
Texas. Well, Liberty goverment publically tries to comply demands of it's citizens, as there're no active enemies to them. Which include removing dangerous scrap in Texas and possibly Kepler. People of Liberty barely felt dangers of Leeds smog, for example.
However in Liberty terraforming isn't looked upon usually. Los Angeles was terraformed long ago (and a bit unsuccesfully, according to Liberty Lore [not sure where I found it, but definately on those forums]), Pittsbourgh, Atka and California Minor are already being terraformed.
Kusari is clean due to work of the Hogosha, they haven't any terraforming posts [exluding Miuru, but that can be ignored, because that's GMG space].
I'm sure there could be some Green Front movements within Bretonian part of Colonial Republic (they have one planet they're "planetforming"), however other citizens of Colonial Republic didn't feel Leeds smog or New London junk yet, so Green Front isn't really popular there - it's tolerated, nothing else.
